Ebook Diagnostic imaging head and neck (2nd edition): Part 1

(BQ) Part 1 book Diagnostic imaging head and neck presents the following contents: Suprahyoid and infrahyoid neck (parapharyngeal space, pharyngeal mucosal space, pharyngeal mucosal space,...), squamous cell carcinoma (pediatric lesions, primary sites, perineural tumor and nodes), pediatric and syndromic diseases (pediatric lesions, pediatric lesions).

Table of Contents

Authors 12

Dedication 14

Case Contributors 14

Preface 15

Acknowledgements 16

Part I - Suprahyoid and Infrahyoid Neck 16

Section 1 - Introduction and Overview 16

Suprahyoid and Infrahyoid Neck Overview 16

Section 2 - Parapharyngeal Space 23

Introduction and Overview 23

Parapharyngeal Space Overview 23

Benign Tumors 26

Parapharyngeal Space Benign Mixed Tumor 26

Section 3 - Pharyngeal Mucosal Space 29

Introduction and Overview 29

Pharyngeal Mucosal Space Overview 29

Congenital Lesions 34

Tornwaldt Cyst 34

Infectious and Inflammatory Lesions 37

Retention Cyst of Pharyngeal Mucosal Space 37

Tonsillar Inflammation 40

Tonsillar/Peritonsillar Abscess 43

Benign and Malignant Tumors 46

Benign Mixed Tumor of Pharyngeal Mucosal Space 46

Non-Hodgkin Lymphoma of Pharyngeal Mucosal Space 49

Masticator Space Overview 55

Section 4 - Masticator Space 60

Introduction and Overview 60

Pterygoid Venous Plexus Asymmetry 60

Pseudolesions 63

Benign Masticator Muscle Hypertrophy 63

CNV3 Motor Denervation 66

Infectious Lesions 72

Masticator Space Abscess 72

Benign Tumors 78

Masticator Space CNV3 Schwannoma 78

Malignant Tumors 81

Masticator Space CNV3 Perineural Tumor 81

Masticator Space Chondrosarcoma 87

Masticator Space Sarcoma 93

Section 5 - Parotid Space 99

Introduction and Overview 99

Parotid Space Overview 99

Infectious and Inflammatory Lesions 104

Acute Parotitis 104

Parotid Sjogren Syndrome 110

Benign Lymphoepithelial Lesions-HIV 116

Benign Tumors 122

Parotid Benign Mixed Tumor 122

Warthin Tumor 128

Parotid Schwannoma 134

Malignant Tumors 137

Parotid Mucoepidermoid Carcinoma 137

Metastatic Disease of Parotid Nodes 155

Section 6 - Carotid Space 161

Introduction and Overview 161

Carotid Space Overview 161

Normal Variants 166

Tortuous Carotid Artery in Neck 166

Vascular Lesions 169

Carotid Artery Dissection in Neck 169

Carotid Artery Pseudoaneurysm in Neck 175

Carotid Artery Fibromuscular Dysplasia in Neck 178

Acute Idiopathic Carotidynia 181

Jugular Vein Thrombosis 184

Post-Pharyngitis Venous Thrombosis (Lemierre) 190

Benign Tumors 193

Carotid Body Paraganglioma 193

Glomus Vagale Paraganglioma 199

Carotid Space Schwannoma 206

Sympathetic Schwannoma 212

Carotid Space Neurofibroma 215

Carotid Space Meningioma 218

Section 7 - Retropharyngeal Space 221

Introduction and Overview 221

Retropharyngeal Space Overview 221

Infectious and Inflammatory Lesions 226

Reactive Adenopathy of Retropharyngeal Space 226

Suppurative Adenopathy of Retropharyngeal Space 229

Retropharyngeal Space Abscess 232

Retropharyngeal Space Edema 238

Metastatic Tumors 244

Nodal SCCa of Retropharyngeal Space 244

Nodal Non-Hodgkin Lymphoma in Retropharyngeal Space 247

Non-SCCa Metastatic Nodes in Retropharyngeal Space 250

Section 8 - Perivertebral Space 253

Introduction and Overview 253

Perivertebral Space Overview 253

Pseudolesions 258

Levator Scapulae Muscle Hypertrophy 258

Infectious and Inflammatory Lesions 261

Acute Calcific Longus Colli Tendonitis 261

Perivertebral Space Infection 264

Vascular Lesions 270

Vertebral Artery Dissection in Neck 270

Benign and Malignant Tumors 273

Brachial Plexus Schwannoma in Perivertebral Space 273

Chordoma in Perivertebral Space 276

Vertebral Body Metastasis in Perivertebral Space 279

Section 9 - Posterior Cervical Space 285

Introduction and Overview 285

Posterior Cervical Space Overview 285

Benign Tumors 288

Posterior Cervical Space Schwannoma 288

Metastatic Tumors 294

SCCa in Spinal Accessory Node 294

Non-Hodgkin Lymphoma in Spinal Accessory Node 297

Section 10 - Visceral Space 300

Introduction and Overview 300

Visceral Space Overview 300

Inflammatory Lesions 305

Chronic Lymphocytic Thyroiditis (Hashimoto) 305

Metabolic Disease 308

Multinodular Goiter 308

Benign Tumors 314

Thyroid Adenoma 314

Parathyroid Adenoma in Visceral Space 320

Malignant Tumors 326

Differentiated Thyroid Carcinoma 326

Medullary Thyroid Carcinoma 332

Anaplastic Thyroid Carcinoma 338

Non-Hodgkin Lymphoma of Thyroid 344

Parathyroid Carcinoma 347

Cervical Esophageal Carcinoma 350

Miscellaneous 353

Esophagopharyngeal Diverticulum (Zenker) 353

Colloid Cyst of Thyroid 356

Lateral Cervical Esophageal Diverticulum 357

Section 11 - Hypopharynx, Larynx, and Cervical Trachea 359

Introduction and Overview 359

Hypopharynx, Larynx, & Trachea Overview 359

Infectious and Inflammatory Lesions 366

Croup 366

Epiglottitis in a Child 370

Supraglottitis 371

Trauma 372

Laryngeal Trauma 372

Benign and Malignant Tumors 378

Upper Airway Infantile Hemangioma 378

Laryngeal Chondrosarcoma 382

Treatment-related Lesions 387

Post-Radiation Larynx 387

Miscellaneous 391

Laryngocele 391

Vocal Cord Paralysis 396

Acquired Subglottic-Tracheal Stenosis 402

Section 12 - Lymph Nodes 408

Introduction and Overview 408

Lymph Node Overview 408

Infectious and Inflammatory Lesions 414

Reactive Lymph Nodes 414

Suppurative Lymph Nodes 420

Tuberculous Lymph Nodes 426

Non-TB Mycobacterium Nodes 429

Sarcoidosis Lymph Nodes 430

Giant Lymph Node Hyperplasia (Castleman) 432

Histiocytic Necrotizing Lymphadenitis (Kikuchi) 438

Kimura Disease 441

Malignant Tumors 447

Nodal Non-Hodgkin Lymphoma in Neck 447

Nodal Hodgkin Lymphoma in Neck 453

Nodal Differentiated Thyroid Carcinoma 459

Systemic Nodal Metastases in Neck 462

Section 13 - Trans-spatial and Multi-spatial 465

Introduction and Overview 465

Trans-spatial & Multi-spatial Overview 465

Normal Variants 468

Prominent Thoracic Duct in Neck 468

Plexiform Neurofibroma of H&N 480

Malignant Tumors 483

Post-Transplantation Lymphoproliferative Disorder 483

Extraosseous Chordoma 486

Non-Hodgkin Lymphoma of H&N 489

Liposarcoma of H&N 495

Synovial Sarcoma of H&N 498

Malignant Peripheral Nerve Sheath Tumor of H&N 501

Miscellaneous 504

Lymphocele of Neck 504

Sinus Histiocytosis (Rosai-Dorfman) of H&N 507

Fibromatosis of H&N 510

Section 14 - Oral Cavity 516

Introduction and Overview 516

Oral Cavity Overview 516

Pseudolesions 523

Hypoglossal Nerve Motor Denervation 523

Congenital Lesions 525

Submandibular Space Accessory Salivary Tissue 525

Oral Cavity Dermoid and Epidermoid 528

Oral Cavity Lymphatic Malformation 534

Lingual Thyroid 538

Infectious and Inflammatory Lesions 541

Ranula 541

Oral Cavity Sialocele 546

Submandibular Gland Sialadenitis 549

Oral Cavity Abscess 552

Benign Tumors 558

Submandibular Gland Benign Mixed Tumor 558

Palate Benign Mixed Tumor 561

Malignant Tumors 564

Sublingual Gland Carcinoma 564

Submandibular Gland Carcinoma 567

Oral Cavity Minor Salivary Gland Malignancy 570

Submandibular Space Nodal Non-Hodgkin Lymphoma 573

Submandibular Space Nodal SCCa 576

Section 15 - Mandible-Maxilla and Temporomandibular Joint 579

Introduction and Overview 579

Mandible-Maxilla and TMJ Overview 579

Congenital Lesions 586

Solitary Median Maxillary Central Incisor 586

Nonneoplastic Cysts 589

Nasolabial Cyst 589

Periapical Cyst (Radicular) 592

Dentigerous Cyst 595

Simple Bone Cyst (Traumatic) 598

Nasopalatine Duct Cyst 601

Infectious and Inflammatory Lesions 604

TMJ Juvenile Idiopathic Arthritis 604

Mandible-Maxilla Osteomyelitis 607

Tumor-like Lesions 610

TMJ Calcium Pyrophosphate Dihydrate Deposition Disease 610

TMJ Pigmented Villonodular Synovitis 611

TMJ Synovial Chondromatosis 613

Mandible-Maxilla Central Giant Cell Granuloma 615

Benign and Malignant Tumors 619

Ameloblastoma 619

Keratocystic Odontogenic Tumor (Odontogenic Keratocyst) 624

Mandible-Maxilla Osteosarcoma 630

Treatment-related Lesions 634

Mandible-Maxilla Osteonecrosis 634

Part II - Squamous Cell Carcinoma 636

Section 1 - Introduction and Overview 636

Squamous Cell Carcinoma Overview 636

Section 2 - Primary Sites, Perineural Tumor and Nodes 644

Nasopharyngeal Carcinoma 644

Nasopharyngeal Carcinoma 644

Oropharyngeal Carcinoma 650

Lingual Tonsil SCCa 650

Palatine Tonsil SCCa 656

Posterior Oropharyngeal Wall SCCa 662

HPV-Related Oropharyngeal SCCa 664

Oral Cavity Carcinoma 665

Oral Tongue SCCa 665

Floor of Mouth SCCa 671

Alveolar Ridge SCCa 675

Retromolar Trigone SCCa 678

Buccal Mucosa SCCa 681

Hard Palate SCCa 682

Hypopharyngeal Carcinoma 683

Pyriform Sinus SCCa 683

Post-Cricoid Region SCCa 689

Posterior Hypopharyngeal Wall SCCa 691

Laryngeal Carcinoma 692

Supraglottic Laryngeal SCCa 692

Glottic Laryngeal SCCa 698

Subglottic Laryngeal SCCa 701

Perineural Tumor 705

Perineural Tumor Spread 705

Squamous Cell Carcinoma Lymph Nodes 710

Nodal Squamous Cell Carcinoma 710

Section 3 - Post-Treatment Neck 716

Nodal Dissection in Neck 716

Reconstruction Flaps in Neck 719

Expected Changes of Neck Radiation Therapy 722

Complications of Neck Radiation Therapy 723

Part III - Pediatric and Syndromic Diseases 725

Section 1 - Pediatric Lesions 725

Introduction and Overview 725

Congenital Overview 725

Congenital Lesions 730

Lymphatic Malformation 730

Venous Malformation 736

Congenital Vallecular Cyst 742

Thyroglossal Duct Cyst 745

Cervical Thymic Cyst 751

1st Branchial Cleft Cyst 757

2nd Branchial Cleft Cyst 763

3rd Branchial Cleft Cyst 769

4th Branchial Cleft Cyst 775

Dermoid and Epidermoid 781

Trauma 787

Fibromatosis Colli 787

Benign Tumors 790

Infantile Hemangioma 790

Metastatic Neuroblastoma 803

Section 2 - Syndromic Diseases 805

Neurofibromatosis Type 1 805

Neurofibromatosis Type 2 810

Basal Cell Nevus Syndrome 813

PHACES Association 816

Branchiootorenal Syndrome 822

Hemifacial Microsomia 828

Treacher Collins Syndrome 830

Pierre Robin Sequence 831

McCune-Albright Syndrome 834

Cherubism 836

Mucopolysaccharidosis 837

Part IV - Sinonasal Cavities and Orbit 841

Section 1 - Nose and Sinus 841

Introduction and Overview 841

Sinonasal Overview 841

Congenital Lesions 848

Nasolacrimal Duct Mucocele 848

Choanal Atresia 851

Nasal Glioma 857

Nasal Dermal Sinus 863

Frontoethmoidal Cephalocele 869

Congenital Nasal Pyriform Aperture Stenosis 875

Infectious and Inflammatory Lesions 878

Acute Rhinosinusitis 878

Chronic Rhinosinusitis 883

Complications of Rhinosinusitis 889

Allergic Fungal Sinusitis 895

Mycetoma 898

Invasive Fungal Sinusitis 901

Sinonasal Polyposis 907

Solitary Sinonasal Polyp 913

Sinonasal Mucocele 918

Silent Sinus Syndrome 924

Sinonasal Wegener Granulomatosis 927

Nasal Cocaine Necrosis 932

Benign Tumors and Tumor-like Lesions 935

Sinonasal Fibrous Dysplasia 935

Sinonasal Osteoma 938

Sinonasal Ossifying Fibroma 944

Juvenile Angiofibroma 950

Sinonasal Inverted Papilloma 956

Sinonasal Hemangioma 961

Sinonasal Nerve Sheath Tumor 965

Sinonasal Benign Mixed Tumor 966

Malignant Tumors 967

Sinonasal Squamous Cell Carcinoma 967

Esthesioneuroblastoma 973

Sinonasal Adenocarcinoma 979

Sinonasal Melanoma 982

Sinonasal Non-Hodgkin Lymphoma 985

Sinonasal Undifferentiated Carcinoma 991

Sinonasal Adenoid Cystic Carcinoma 993

Sinonasal Chondrosarcoma 994

Sinonasal Osteosarcoma 996

Section 2 - Orbit 997

Introduction and Overview 997

Orbit Overview 997

Congenital Lesions 1002

Coloboma 1002

Persistent Hyperplastic Primary Vitreous 1009

Coats Disease 1012

Orbital Dermoid and Epidermoid 1015

Orbital Neurofibromatosis Type 1 1021

Vascular Lesions 1027

Orbital Lymphatic Malformation 1027

Orbital Venous Varix 1033

Orbital Cavernous Hemangioma 1036

Infectious and Inflammatory Lesions 1042

Ocular Toxocariasis 1042

Orbital Subperiosteal Abscess 1045

Orbital Cellulitis 1051

Orbital Idiopathic Inflammatory Pseudotumor 1055

Orbital Sarcoidosis 1060

Thyroid Ophthalmopathy 1064

Optic Neuritis 1070

Tumor-like Lesions 1076

Orbital Langerhans Cell Histiocytosis 1076

Benign Tumors 1080

Orbital Infantile Hemangioma 1080

Optic Pathway Glioma 1085

Optic Nerve Sheath Meningioma 1091

Lacrimal Gland Benign Mixed Tumor 1097

Malignant Tumors 1101

Retinoblastoma 1101

Ocular Melanoma 1107

Orbital Lymphoproliferative Lesions 1113

Lacrimal Gland Carcinoma 1119

Part V - Skull Base 1122

Section 1 - Skull Base Lesions 1122

Introduction and Overview 1122

Skull Base Overview 1122

Clivus 1128

Ecchordosis Physaliphora 1128

Invasive Pituitary Macroadenoma 1131

Chordoma 1134

Sphenoid Bone 1140

Persistent Craniopharyngeal Canal 1140

Sphenoid Benign Fatty Lesion 1143

Central Skull Base Trigeminal Schwannoma 1145

Occipital Bone 1146

Hypoglossal Nerve Schwannoma 1146

Jugular Foramen 1149

Jugular Bulb Pseudolesion 1149

High Jugular Bulb 1152

Dehiscent Jugular Bulb 1155

Jugular Bulb Diverticulum 1158

Glomus Jugulare Paraganglioma 1161

Jugular Foramen Schwannoma 1167

Jugular Foramen Meningioma 1173

Dural Sinuses 1176

Dural Sinus & Aberrant Arachnoid Granulations 1176

Skull Base Dural Sinus Thrombosis 1181

Cavernous Sinus Thrombosis 1187

Skull Base CSF Leak 1202

Skull Base Fibrous Dysplasia 1205

Skull Base Paget Disease 1210

Skull Base Langerhans Cell Histiocytosis 1213

Skull Base Osteopetrosis 1219

Skull Base Idiopathic Inflammatory Pseudotumor 1222

Skull Base Giant Cell Tumor 1228

Skull Base Meningioma 1231

Skull Base Plasmacytoma 1237

Skull Base Multiple Myeloma 1243

Skull Base Metastasis 1246

Skull Base Chondrosarcoma 1249

Skull Base Osteosarcoma 1255

Section 2 - Skull Base and Facial Trauma 1258

Introduction and Overview 1258

Skull Base and Facial Trauma Overview 1258

Introduction and Overview 1263

Temporal Bone Trauma 1263

Skull Base Trauma 1268

Introduction and Overview 1274

Orbital Foreign Body 1274

Orbital Blowout Fracture 1277

Trans-facial Fracture (Le Fort) 1280

Zygomaticomaxillary Complex Fracture 1285

Complex Facial Fracture 1288

Naso-orbital-ethmoidal Fracture 1290

Mandible Fracture 1291

TMJ Meniscal Dislocation 1294

Part VI - Temporal Bone and CPA-IAC 1297

Section 1 - Introduction and Overview 1297

Temporal Bone Overview 1297

Section 2 - External Auditory Canal 1304

Congenital Lesions 1304

Congenital External Ear Dysplasia 1304

Infectious and Inflammatory Lesions 1310

Necrotizing External Otitis 1310

Keratosis Obturans 1314

Medial Canal Fibrosis 1316

EAC Cholesteatoma 1322

Benign and Malignant Tumors 1325

EAC Osteoma 1325

EAC Exostoses 1328

EAC Skin SCCa 1331

Section 3 - Middle Ear-Mastoid 1334

Congenital Lesions 1334

Congenital Middle Ear Cholesteatoma 1334

Congenital Mastoid Cholesteatoma 1340

Congenital Ossicular Fixation 1341

Oval Window Atresia 1343

Lateralized Internal Carotid Artery 1346

Aberrant Internal Carotid Artery 1348

Persistent Stapedial Artery 1354

Infectious and Inflammatory Lesions 1358

Acute Otomastoiditis with Abscess 1358

Coalescent Otomastoiditis 1363

Chronic Otomastoiditis with Ossicular Erosions 1367

Chronic Otomastoiditis with Tympanosclerosis 1369

Pars Flaccida Cholesteatoma 1373

Pars Tensa Cholesteatoma 1378

Mural Cholesteatoma 1384

Middle Ear Cholesterol Granuloma 1387

Benign and Malignant Tumors 1393

Glomus Tympanicum Paraganglioma 1393

Temporal Bone Meningioma 1399

Middle Ear Schwannoma 1405

Middle Ear Adenoma 1409

Temporal Bone Rhabdomyosarcoma 1412

Miscellaneous 1417

Temporal Bone Cephalocele 1417

Ossicular Prosthesis 1420

Section 4 - Inner Ear 1426

Pseudolesions 1426

Subarcuate Canaliculus 1426

Cochlear Cleft 1429

Congenital Lesions 1433

Labyrinthine Aplasia 1433

Common Cavity Malformation 1435

Cystic Cochleovestibular Malformation (IP-I) 1438

Cochlear Incomplete Partition Type I (IP-I) 1441

Large Vestibular Aqueduct (IP-II) 1444

X-Linked Stapes Gusher (DFNX2) 1450

Cochlear Aplasia 1453

Cochlear Hypoplasia 1456

Cochlear Nerve & Cochlear Nerve Canal Aplasia-Hypoplasia 1459

Globular Vestibule-Semicircular Canal 1462

Semicircular Canal Hypoplasia-Aplasia 1463

CHARGE Syndrome 1465

Infectious and Inflammatory Lesions 1470

Labyrinthitis 1470

Otosyphilis 1474

Labyrinthine Ossificans 1477

Otosclerosis 1482

Benign and Malignant Tumors 1487

Intralabyrinthine Schwannoma 1487

Endolymphatic Sac Tumor 1493

Miscellaneous 1496

Intralabyrinthine Hemorrhage 1496

Semicircular Canal Dehiscence 1499

Cochlear Implants 1502

Section 5 - Petrous Apex 1508

Pseudolesions 1508

Petrous Apex Asymmetric Marrow 1508

Petrous Apex Cephalocele 1511

Congenital Lesions 1514

Congenital Petrous Apex Cholesteatoma 1514

Infectious and Inflammatory Lesions 1520

Petrous Apex Trapped Fluid 1520

Petrous Apex Mucocele 1523

Petrous Apex Cholesterol Granuloma 1526

Apical Petrositis 1532

Vascular Lesions 1538

Petrous Apex ICA Aneurysm 1538

Section 6 - Intratemporal Facial Nerve 1541

Pseudolesions 1541

Intratemporal Facial Nerve Enhancement 1541

Benign and Malignant Tumors 1553

T-Bone Facial Nerve Venous Malformation (Hemangioma) 1553

T-Bone Facial Nerve Schwannoma 1559

T-Bone Perineural Parotid Malignancy 1565

Section 7 - Temporal Bone, No Specific Anatomic Location 1570

T-Bone CSF Leak 1570

T-Bone Arachnoid Granulations 1573

T-Bone Fibrous Dysplasia 1576

T-Bone Paget Disease 1580

T-Bone Langerhans Cell Histiocytosis 1583

T-Bone Metastasis 1586

T-Bone Osteoradionecrosis 1589

Section 8 - CPA-IAC 1592

Introduction and Overview 1592

CPA-IAC Overview 1592

Congenital Lesions 1597

CPA Epidermoid Cyst 1597

CPA Arachnoid Cyst 1603

CPA-IAC Congenital Lipoma 1609

IAC Venous Malformation 1615

Infectious and Inflammatory Lesions 1618

CPA-IAC Meningitis 1618

Ramsay Hunt Syndrome 1621

CPA-IAC Sarcoidosis 1624

Benign and Malignant Tumors 1627

Vestibular Schwannoma 1627

CPA-IAC Meningioma 1633

CPA-IAC Facial Nerve Schwannoma 1639

CPA-IAC Metastases 1642

Vascular Lesions 1648

Trigeminal Neuralgia 1648

Hemifacial Spasm 1651

CPA-IAC Aneurysm 1654

CPA-IAC Superficial Siderosis 1657

Index 1664

A 1664

B 1665

C 1666

D 1671

E 1672

F 1673

G 1674

H 1675

I 1676

J 1677

K 1678

L 1678

M 1681

N 1684

O 1686

P 1689

R 1693

S 1695

T 1701

U 1704

V 1704

W 1705

X 1706

Z 1706

Authors

Authors

H Ric Harnsberger MD

Professor of Radiology and Otolaryngology

R.C Willey Chair in Neuroradiology

University of Utah School of Medicine

Salt Lake City, UT

Christine M Glastonbury MBBS

Associate Professor

Radiology and Biomedical Imaging, Otolaryngology - Head

and Neck Surgery, and Radiation Oncology

University of California, San Francisco

San Francisco, CA

Michelle A Michel MD

Professor of Radiology and Otolaryngology

Chief, Head and Neck Neuroradiology

Medical College of Milwaukee

Milwaukee, WI

Bernadette L Koch MD

Associate Professor of Radiology and Pediatrics

University of Cincinnati College of Medicine

Associate Director of Physician Services and Education

Cincinnati Children's Hospital Medical Center

Cincinnati, OH

Barton F Branstetter IV MD

Associate Professor of Radiology, Otolaryngology, and Biomedical Informatics University of Pittsburgh School of Medicine

Director of Head and Neck Imaging

University of Pittsburgh Medical Center

Pittsburgh, PA

H Christian Davidson MD

Associate Professor of Radiology

University of Utah School of Medicine

Salt Lake City, UT

Deborah R Shatzkes MD

Director of Head and Neck Imaging

St Lukes - Roosevelt Hospital Center

Associate Professor of Radiology

Columbia University College of Physicians and Surgeons

New York, NY

Rebecca S Cornelius MD

Professor of Radiology and Otolaryngology - Head and Neck Surgery

University of Cincinnati College of Medicine

University Hospital - UC Health

Cincinnati, OH

P.iii

Troy Hutchins MD

Assistant Professor of Radiology and Neurosurgery

University of California, Irvine

Orange, CA

C Douglas Phillips MD, FACR

Professor of Radiology

New York Presbyterian Hospital

New York, NY

Patricia A Hudgins MD, FACR

Professor of Radiology and Otolaryngology

Director of Head and Neck Radiology

Department of Radiology

Emory University School of Medicine

Atlanta, GA

Kristine M Mosier DMD, PhD

Associate Professor of Radiology

Chief, Head and Neck Radiology

Indiana University

Department of Radiology & Imaging Sciences

Indianapolis, IN

Caroline D Robson MBChB

Associate Professor of Radiology

Harvard Medical School

Operations Vice Chair, Radiology

Director of Head and Neck Imaging

Children's Hospital, Boston

Boston, MA

Hilda E Stambuk MD

Associate Attending of Radiology

Clinical Head of Head and Neck Imaging

Memorial Sloan - Kettering Cancer Center

New York, NY

Associate Professor of Radiology

Weill Medical College of Cornell University

New York, NY

Karen L Salzman MD

Associate Professor of Radiology

Leslie W Davis Endowed Chair in Neuroradiology

University of Utah School of Medicine

Salt Lake City, UT

Richard H Wiggins III MD

Associate Professor

Department of Radiology, Otolaryngology -

Head and Neck Surgery, and BioMedical Informatics

University of Utah School of Medicine

Salt Lake City, UT

Contributing Authors

Philip R Chapman, MD

Assistant Professor of Neuroradiology

University of Alabama, Birmingham

Birmingham, AL

Yolanda Y.P Lee, MBChB, FRCR

Honorary Associate Professor

Department of Imaging and Interventional Radiology

The Chinese University of Hong Kong

Hong Kong SAR

Bronwyn E Hamilton, MD

Associate Professor of Radiology

Director MRI Department of Radiology

Neuroradiology Division

Oregon Health & Science University

Portland, OR

Lawrence E Ginsberg, MD

Professor of Radiology and Head and Neck Surgery

The University of Texas M.D Anderson Cancer Center

Also thanks to the “home team” at Amirsys central who performed miracles in creating this dynamite work

Specifically thanks to Ashley, Kellie, Arthur, Kate, Dave, and Jeff (our awesome editorial team), Rich (our superb medical illustrator), and Mike (our Production Director) Paula, my sister separated at birth and my partner in the Amirsys dream, the whole thing is impossible without you Paul and Julia, thanks for your friendship and amazing ability to see the big picture

Finally thanks to my family, Jungle J (74?) and Dave, Dan, and Dylan I know that every time I start talking about the next book, you all cringe Take heart, I think this is the last big book that was stuck inside yearning to come into the light To Doris and Hutch, you gave me more than enough love to get me through Wish you could have seen this day

H R H

A book like this only happens with dedication and hard work from every level in the production team at Amirsys and from a true team of authors Together we've “placed oars in the water,” “gone over the falls in a barrel,” “circled our wagons,” “pushed our noses across the tape,” and counted “bottles of beer on the wall” to “the end of the

marathon.” It's been a long, extraordinary, and fun trip Thank you all! Every day I am honored to work with, learn from, and be inspired by amazing radiologists, ENT surgeons, and radiation oncologists I especially thank Bill and Jim and all my Neuro colleagues at UCSF And of course I thank Ric for taking a chance on a registrar from Adelaide and opening up this world of H&N to me! Thanks, Boss

B L K

Case Contributors

Below are listed the important group of radiologists who took the time to help find the case material necessary to fill the extensive image galleries of Diagnostic Imaging: Head and Neck, 2nd edition Without their willingness to “share the wealth,” this book would have been far less rich an offering

Thank you all so much for your generous natures and avid interest in this project No book of this nature could have been done alone!

Ric, Christine, Michelle, and Bernadette

Anil T Ahuja; Hong Kong, China

Hank Baskin; Salt Lake City, UT

Nancy Fischbein; Palo Alto, CA

Lindell Gentry; Madison, WI

Lawrence E Ginsberg; Houston, TX

Julian Goh; Singapore

Gary L Hedlund; Salt Lake City, UT

Peter Hildenbrand; Burlington, MA

Tim Larsen; Seattle, WA

Laurie Loevner; Philadelphia, PA

Yolanda Lee; Hong Kong, China

Lisa Lowe; Kansas City, MO

André Macdonald, MBChB; Salt Lake City, UT

Karen Moeller; Louisville, KY

Kevin Moore; Salt Lake City, UT

Brian Psooy; Halifax, Canada

Jeff Ross; Phoenix, AZ

Marlin Sandlin; Houston, TX

Charles Schatz; Los Angeles, CA

Anthony J Scuderi; Johnstown, PA

Lubdha Shah; Salt Lake City, UT

Brian Steele; Denver, CO

Robert Wallace; Phoenix, AZ

Preface

This stunning (if we do say so ourselves) 2nd edition of Diagnostic Imaging: Head and Neck represents the most comprehensive single volume textbook in the field of Head and Neck Imaging today As you might expect there are many new and exciting features in the second edition We've improved but kept the basic layout so that the same information is in the same place—every time, in every chapter We've added 120 new diagnoses, 2500 new images, and 300 of our signature color graphics The references have all been updated to within a few weeks of publication What else makes the second edition significantly different? The most important new feature are the 23 new prose introductions at the front of each of the book's sections The goal of these introductions is to guide the reader through the relevant anatomy and approaches to imaging issues in each area of the head and neck Another key update comes from the fact that in each of the diagnosis chapters virtually all of the gallery images have been replaced with newer, more advanced imaging examples of each diagnosis As there were no eBook images in the first edition, the 1700 images in the eBook galleries give a rich additional perspective for each diagnosis chapter

On a global content level, the 2nd edition of Diagnostic Imaging: Head and Neck now contains an all new 24-chapter

“Squamous Cell Carcinoma” section that follows the same primary site organization (pharynx, oral cavity, and larynx)

of the American Joint Committee on Cancer A second brand new area in the book is the 27-chapter “Pediatric & Syndromic Diseases” section

Our reason for writing this book in the simplest terms was to contribute to the process of demystifying the field of Head & Neck Imaging We want Diagnostic Imaging: Head and Neck, second edition to be your favorite Head & Neck Imaging text—used, worn, dog-eared, and loved To this end, we welcome any ideas, comments or suggestions If you email them to feedback@amirsys.com, we will respond to your ideas and implement them as possible

Thanks for making the books in our Diagnostic Imaging series the bestsellers they so quickly became We hope you enjoy this sequel!

H Ric Harnsberger, MD

Professor of Radiology & Otolaryngology

R C Willey Chair in Neuroradiology

University of Utah School of Medicine

Salt Lake City, UT

Summary of “What's New in DI: H&N Two”

 Two all new book sections

o “Squamous Cell Carcinoma” section

o “Pediatric & Syndromic Diseases” section

 Comparisons of first vs second editions Diagnostic Imaging: Head and Neck:

o New pages = 200

o New diagnoses = 120

o New color graphics = 300

o eBook images = 1700

o New prose introductions = 23

o All new images in chapter galleries (2800 total book images)

Part I - Suprahyoid and Infrahyoid Neck

Section 1 - Introduction and Overview

Suprahyoid and Infrahyoid Neck Overview

> Table of Contents > Part I - Suprahyoid and Infrahyoid Neck > Section 1 - Introduction and Overview > Suprahyoid and Infrahyoid Neck Overview

Suprahyoid and Infrahyoid Neck Overview

H Ric Harnsberger, MD

Imaging Approaches & Indications

Neither CT nor MR is a perfect modality in imaging the extracranial H&N MR is most useful in the SHN because it is less affected by oral cavity dental amalgam artifact Since the SHN tissue is less affected by motion compared to the IHN, MR image quality is not degraded by movement seen in the IHN Axial & coronal T1 fat-saturated enhanced MR is superior to CECT in defining soft tissue extent of tumor, perineural tumor spread, & dural/intracranial spread When

MR is combined with bone CT of the facial bones & skull base, precise preoperative lesion mapping results

CECT is the modality of choice when IHN & mediastinum are imaged Swallowing, coughing, & breathing makes this area a “moving target” for the imager MR image quality is often degraded as a result Multislice CT with multiplanar reformations now permit exquisite images of the IHN unaffected by movement

High-resolution ultrasound also has a role Superficial lesions, thyroid disease, & nodal evaluation with biopsy are best done by skilled ultrasonographers

Many indications exist for imaging the extracranial H&N “Exploratory” imaging, tumor staging, & abscess search comprise 3 common reasons imaging is ordered in this area “Exploratory” imaging, an imaging search for any lesion that may be causing the patient's symptoms, is best completed with CECT from skull base to the clavicles

Squamous cell carcinoma (SCCa) staging is best started with CECT as both the primary tumor & nodes must be imaged, requiring imaging from the skull base to clavicles MR imaging times and susceptibility to motion artifact make it a less desirable exam in this setting Instead, MR is best used when specific delineation of exact tumor extent, perineural tumor, or intracranial invasion is needed

When the type & cause of H&N infection are sought, CECT is the best exam CECT can readily differentiate cellulitis, phlegmon, & abscess CT can also identify salivary gland ductal calculi, teeth infection, mandible osteomyelitis, &

In discussing the extracranial H&N soft tissues, a few definitions are needed The SHN is defined as deep facial spaces above hyoid bone, including parapharyngeal space (PPS), pharyngeal mucosal space (PMS), masticator space (MS), parotid space (PS), carotid space (CS), retropharyngeal space (RPS), danger space (DS), & perivertebral (PVS) space The IHN soft tissue spaces are predominantly below hyoid bone, with some continuing inferiorly into the mediastinum

or superiorly into the SHN, including the visceral space (VS), posterior cervical space (PCS), CS, RPS, & PVS

Important SHN space anatomic relationships include their interactions with the skull base, oral cavity, & infrahyoid neck When thinking about the SHN spaces and their relationships with the skull base, perhaps the most important consideration is to examine each space alone to see what critical structures (cranial nerves, arteries, veins) are at the point of contact between the space & the skull base Space by space, the skull base interactions above & IHN

extension below are apparent

 The PPS has a bland triangular skull base abutment without critical foramen involved; it empties inferiorly into submandibular space (SMS)

 The PMS touches the posterior basisphenoid & anterior basiocciput, including foramen lacerum; the PMS includes nasopharyngeal, oropharyngeal, & hypopharyngeal mucosal surfaces

 The MS cephalad skull base interaction includes the zygomatic arch, condylar fossa, & roof of infratemporal fossa, including foramen ovale (CNV3) & foramen spinosum; the MS ends at inferior surface of body of mandible

 The PS abuts the floor of EAC, mastoid tip including stylomastoid foramen (CN7); the parotid tail extends inferiorly into posterior SMS

 The CS meets the jugular foramen (CN9-11) floor, hypoglossal canal (CN12), & petrous ICA canal; CS can be followed inferiorly to the aortic arch

 The RPS contacts the skull base along the lower clivus without involvement of critical structures; it continues inferiorly to empty into DS at T3 level

 The PVS touches the low clivus, encircles occipital condyles & foramen magnum; the PVS continues inferiorly

to level into the thorax

In addition to skull base interactions, the relationships of the SHN spaces to the fat-filled PPSs are key to analyzing SHN masses The PPSs are a pair of fat-filled spaces in the lateral SHN surrounded by the PMS, MS, PS, CS, & RPS When a mass enlarges in one of these spaces, it displaces the PPS fat Larger masses define their space of origin based

on this displacement pattern

 The medial PMS mass displaces the PPS laterally

 The more anterior MS mass displaces PPS posteriorly

 The lateral PS mass displaces the PPS medially

 The posterolateral CS mass displaces styloid process & PPS anteriorly

 The more posteromedial lateral RPS nodal mass displaces PPS anterolaterally

The IHN spaces anatomic relationships are defined by their superior & inferior projections The VS has no SHN

component, instead projecting only inferiorly into the superior mediastinum The PCS extends superiorly to the mastoid tip & ends inferiorly at the clavicle It is predominantly an IHN space however The CS begins at the floor of jugular foramen & carotid canal & extends inferiorly to the aortic arch The RPS begins at clivus superiorly and

traverses SHN-IHN to T3 level The DS is immediately posterior to the RPS but continues beyond T3 level into

mediastinum For imaging purposes, RPS & DS can be considered a single entity The PVS can be defined from skull base above to clavicle below The PVS is divided by fascial slip into prevertebral & paraspinal components

Nobody likes to study the deep cervical fasciae of the neck However, it is these fasciae that define the very spaces we use to subdivide neck diseases & construct space-specific differential diagnosis lists It is imperative that a clear understanding of these fasciae be grasped by any imager involved in evaluating this area

Many nomenclatures have been used to describe the neck fascia The following is a practical distillate meant to simplify this challenging subject There are 3 main deep cervical fascia in the neck The same names are used in the SHN & IHN The superficial layer (SL-DCF), the middle layer (ML-DCF), & deep layer of deep cervical fascia (DL-DCF) are the 3 important fascia in the neck

In the SHN, the SL-DCF circumscribes MS & PS and contributes to carotid sheath In the IHN, it “invests” neck

The internal structures of the spaces of the neck are for the most part responsible for the diseases there Let's begin

by defining the critical contents of the SHN spaces:

 The PPS contains fat only

 The PMS contains mucosa, lymphatic ring, & minor salivary glands The nasopharyngeal mucosal space, the opening of eustachian tube, torus tubarius, adenoids, superior constrictor, & levator palatini muscles can be found The oropharyngeal mucosal space contains the anterior & posterior tonsillar pillars, palatine, & lingual tonsils

 The MS includes the mandible body & ramus, TMJ, CNV3, masseter, medial & lateral pterygoid & temporalis muscles, & pterygoid venous plexus

 The PS houses the parotid, extracranial CN7 nodes, retromandibular vein, & external carotid artery

 The CS contains the CN9-12, internal jugular vein, and internal carotid artery

 The RPS has fat, medial & lateral RPS nodes inside

 The prevertebral PVS contains vertebral body, veins & arteries, & prevertebral muscles (longus colli & capitis); in the paraspinal PVS resides the posterior elements of vertebra & the paraspinal muscles

The critical contents of IHN spaces are defined next

 The VS contains the thyroid & parathyroid glands, trachea, esophagus, recurrent laryngeal nerves, and pretracheal & paratracheal nodes

 The PCS has fat, CN11, & level V nodes inside

 The CS houses the common carotid artery, internal jugular vein, and CN10

 The IHN RPS has no nodes & contains only fat

 The prevertebral PVS has the brachial plexus & phrenic nerve, vertebral body, veins & arteries, prevertebral

& scalene muscles within The paraspinal PVS contains only the posterior vertebra elements & paraspinal muscles

Approaches to Imaging Issues in SHN & IHN

It is important that the imager has a method of analysis when a mass is found in the neck In the SHN, mass evaluation methodology begins with defining mass space of origin (PMS, MS, PS, CS, lateral RPS) When small, this is simple as the mass is seen within the confines of 1 space In larger masses, ask the question, “How does the mass displace the PPS?” Next, utilize a space-specific differential diagnosis list Match the imaging findings to the diagnoses within this list to narrow your differential

With IHN masses, a similar evaluation methodology can be employed First, determine what space the mass originates

in (VS, CS, PCS, ACS) Then, review space-specific differential diagnosis list Match radiologic findings of your case to this DDx list In all neck masses, knowing the clinical findings can be very helpful

Lesions of the posterior midline spaces (RPS & PVS) of the neck require a different image evaluation approach When

a lesion is defined here, first ask the question, “How does mass displace prevertebral muscles (PVM)?” In the case of a RPS mass, the PVMs are flattened posteriorly or invaded from anterior to posterior Contrast this imaging appearance

to that of the PVS mass where the PVMs are lifted anteriorly or invaded from posterior to anterior Since most PVS lesions arise from vertebral body, vertebral body destruction & epidural disease will be associated The DL-DCF

“forces” PVS disease into the epidural space

There are many pseudolesions of extracranial H&N Always begin your image analysis by considering if the “lesion” you see is a normal structure, normal variant, or a “leave me alone” lesion A common pitfall is to mistake a motor denervation for an intrinsic disease In acute-subacute muscle denervation, swelling with contrast enhancement is seen In chronic denervation, muscle volume loss & fatty infiltration is the rule Five motor atrophy patterns can be seen in the H&N They are CNV3, CN7, CN10, CN11, and CN12

Selected References

1 Harnsberger HR et al: Differential diagnosis of head and neck lesions based on their space of origin 1 The

suprahyoid part of the neck AJR Am J Roentgenol 157(1):147-54, 1991

2 Smoker WR et al: Differential diagnosis of head and neck lesions based on their space of origin 2 The infrahyoid portion of the neck AJR Am J Roentgenol 157(1):155-9, 1991

Tables

Common Tumors in the Spaces of the Neck

Pharyngeal mucosal

space

Masticator space Carotid body paraganglioma Differentiated thyroid carcinoma

Perineural CNV3 SCCa Retropharyngeal space Differentiated thyroid carcinoma

Parotid space SCCa nodal metastasis Anaplastic thyroid carcinoma

Mucoepidermoid

carcinoma

Image Gallery

(Top) Axial graphic depicts the spaces of the suprahyoid neck Surrounding the paired fat-filled parapharyngeal spaces are the 4 critical paired spaces of this region, the pharyngeal mucosal, masticator, parotid, and carotid spaces The

retropharyngeal and perivertebral spaces are the midline nonpaired spaces A PMS mass pushes the PPS laterally, an

MS mass pushes the PPS posteriorly, a PS mass pushes the PPS medially, and a CS mass pushes the PPS anteriorly Lateral RPS mass will push the PPS anteriorly without lifting the styloid process The superficial (yellow line), middle (pink line), & deep (turquoise line) layers of deep cervical fascia outline the spaces (Bottom) Axial contrast-enhanced

CT image at the level of the nasopharyngeal suprahyoid neck shows the 4 key spaces surrounding the parapharyngeal space: The pharyngeal mucosal, masticator, parotid, and carotid spaces Notice the retropharyngeal fat stripe is not seen in the high nasopharynx between the prevertebral muscles and the pharyngeal mucosal surface

P.I(1):5

(Top) Axial graphic shows the suprahyoid neck spaces at the level of the oropharynx The superficial (yellow line), middle (pink line), and deep (turquoise line) layers of deep cervical fascia outline the suprahyoid neck spaces Notice the lateral borders of the retropharyngeal & danger spaces are called the alar fascia, which represents a slip of the

retropharyngeal space The alar fascia that makes up the lateral borders of the retropharyngeal space are not shown.P.I(1):6

(Top) Axial graphic depicts the fascia and spaces of the infrahyoid neck The 3 layers of deep cervical fascia are present

in the suprahyoid and infrahyoid neck The carotid sheath is made up of all 3 layers of deep cervical fascia (tricolor line around carotid space) Notice the deep layer (turquoise line) completely circles the perivertebral space, diving in laterally to divide it into prevertebral and paraspinal components The middle layer (pink line) circumscribes the visceral space while the superficial layer (yellow line) “invests” the neck deep tissues (Bottom) In this axial CECT image, the middle layer of deep cervical fascia is drawn to delineate the margins of the visceral space The visceral space contains the high-density thyroid gland, the upper cervical esophagus, and the cricoid cartilage The carotid spaces are lateral to the visceral space, while the retropharyngeal and perivertebral spaces are posterior

P.I(1):7

(Top) Coronal graphic shows suprahyoid neck spaces as they interact with the skull base The masticator space has the largest area of abutment with the skull base, including CNV3 The pharyngeal mucosal space abuts the basisphenoid and foramen lacerum The foramen lacerum is the cartilage-covered floor of the anteromedial petrous internal carotid artery canal (Bottom) Sagittal graphic depicts longitudinal spatial relationships of the infrahyoid neck Anteriorly, the visceral space is seen surrounded by middle layer of deep cervical fascia (pink line) Just anterior to the vertebral column, the retropharyngeal and danger spaces run inferiorly toward the mediastinum Notice the fascial “trap door” found at the approximate level of T3 vertebral body that serves as a conduit from the retropharyngeal to the danger space Retropharyngeal space infection or tumor may access the mediastinum via this route of spread.

Section 2 - Parapharyngeal Space

Introduction and Overview

Parapharyngeal Space Overview

> Table of Contents > Part I - Suprahyoid and Infrahyoid Neck > Section 2 - Parapharyngeal Space > Introduction and Overview > Parapharyngeal Space Overview

Parapharyngeal Space Overview

H Ric Harnsberger, MD

Summary Thoughts: Parapharyngeal Space

The four key spaces of the suprahyoid neck surround the parapharyngeal space (PPS), which is a central fatfilled lateral suprahyoid neck (SHN) space When large lesions of the SHN become hard to localize to a space of origin, the direction of the PPS displacement may be used in combination with the space where most of the tumor is located to make a definite determination as to where the lesion originated Once a space of origin is assigned, the space-specific differential diagnosis can be applied to narrow the diagnostic possibilities

Imaging Anatomy

The parapharyngeal spaces are central, fat-filled spaces in lateral suprahyoid neck around which most of the

important spaces are located These surrounding important spaces are the pharyngeal mucosal space (PMS),

masticator space (MS), parotid space (PS), carotid space (CS), and the lateral retropharyngeal space (RPS) The PPS contents are limited; therefore, few lesions actually occur in this space Diseases (tumor and infection) of PPS usually arise in adjacent spaces (PMS, MS, PS, CS), spreading secondarily into PPS

The importance of the fat-filed PPS is its conspicuity on CT and MR Even when large lesions are present in the SHN, it

is still usually possible to find the PPS Identifying the direction of displacement of the PPS by a mass lesion from a surrounding space can be a key finding in determining its space of origin The PPS displacement direction defines the space of the primary lesion

 PMS mass lesion pushes PPS laterally

 MS mass lesion pushes PPS posteriorly

 PS mass lesion pushes PPS medially

 CS mass lesion pushes PPS anteriorly

 Lateral retropharyngeal space mass (nodal) pushes PPS anterolaterally

The PPS is a crescent-shaped fat-filled space in craniocaudal dimension extending from the skull base superiorly to the superior cornu of hyoid bone inferiorly As paired fatty tubes separating other SHN spaces from one another, the PPS functions as an “elevator shaft” through which infection and tumor from these adjacent spaces may travel from the skull base to the hyoid bone

The PPS has multiple important anatomic relationships with surrounding spaces As there is no fascia separating the inferior PPS from the submandibular space (SMS), open communication between the PPS and posterior SMS exists Superiorly PPS interacts with the skull base in bland triangular area on the inferior surface of the petrous apex No exiting skull base foramina are found in this area of attachment In the axial plane the PMS is medial, the MS anterior, the PS lateral, the CS posterior, and the lateral RPS posteromedial to the parapharyngeal space

PPS internal structures are few There is no mucosa, muscle, bone, nodes, or major salivary gland tissue within the PPS boundaries The PPS principal content is fat Minor salivary glands can be found there but are ectopic and rare Although most of the pterygoid venous plexus is in the deep portion of the masticator space, a part of the plexus spills into the PPS

The fascia surrounding the PPS is complex Different layers of the deep cervical fascia combine to circumscribe the PPS The medial fascial margin of PPS is made up of the middle layer of deep cervical fascia as it curves around lateral margin of PMS The lateral fascial margin of the PPS is comprised of the medial slip of superficial layer of deep cervical fascia along the deep border of the MS and PS The posterior fascial margin of the PPS is formed by the deep layer of deep cervical fascia on the anterolateral margin of the retropharyngeal space and the anterior part of the carotid sheath (made up of components of all three layers of deep cervical fascia)

Clinical Implications

Since the PPS empties inferiorly into the SMS, PPS infection or malignancy spread inferiorly from the upper SHN to present as “angle of mandible” mass

Approaches to Imaging Issues of the Parapharyngeal Space

When you discover a lesion in the PPS on CT or MR, answer the following question first: “Is this lesion really primary to the PPS?” This question needs to be answered because there are so few things that occur initially in the PPS In fact, the vast majority of lesions of the PPS arise in adjacent spaces and spread from there into the PPS To conclude that a

lesion is primary to the PPS, it must be completely surrounded by PPS fat In most cases where a lesion is thought to

be primary to PPS, careful observation will find a connection to one of the surrounding spaces

Lesions that are primary to the PPS itself include atypical 2nd branchial cleft cyst, benign mixed tumor, and lipoma All are rare Far more common lesions can be seen spreading into the PPS, such as intratonsillar abscess becoming peritonsillar and squamous cell carcinoma of the nasopharynx and oropharyngeal palatine tonsil When a large, parotid deep lobe benign mixed tumor pedunculates into the PPS, it may at first glance appear to be primary to the PPS Careful inspection will reveal a connection to the deep lobe of the parotid in the vast majority of cases

Differential Diagnosis

DDx of parapharyngeal space lesion

 Congenital: Atypical 2nd branchial cleft cyst, lymphatic malformation, venous malformation

 Inflammatory: Large diving ranula spreading from submandibular space into PPS

 Infection: Peritonsillar abscess spreading from palatine tonsil into PPS

 Benign tumor: Lipoma, benign mixed tumor

 Malignant tumor: SCCa spreading from naso- or oropharynx into PPS

3 Stambuk HE et al: Imaging of the parapharyngeal space Otolaryngol Clin North Am 41(1):77-101, vi, 2008

4 Monobe H et al: Peritonsillar abscess with parapharyngeal and retropharyngeal involvement: incidence and intraoral approach Acta Otolaryngol Suppl (559):91-4, 2007

P.I(2):3

Image Gallery

(Top) Axial graphic of the normal parapharyngeal space at the level of the nasopharynx demonstrates the complex fascial margins and the fat-only contents Mass lesions originating in the surrounding pharyngeal mucosal, masticator, parotid, and carotid spaces can extend into the parapharyngeal space The resulting displacement pattern of the parapharyngeal space may be helpful in defining the space of origin of a mass in the suprahyoid neck (Bottom) Coronal graphic shows suprahyoid neck spaces as they interact with the skull base superiorly and submandibular space inferiorly The parapharyngeal space interacts with no critical structures as it abuts the skull base Inferiorly it

“empties” into the posterior submandibular space along the posterior margin of the mylohyoid muscle As a

consequence of this anatomic arrangement, it is possible for an infection or a malignant tumor that breaks into the parapharyngeal space to present inferiorly as an “angle of mandible” mass

Benign Tumors

Parapharyngeal Space Benign Mixed Tumor

> Table of Contents > Part I - Suprahyoid and Infrahyoid Neck > Section 2 - Parapharyngeal Space > Benign Tumors > Parapharyngeal Space Benign Mixed Tumor

Parapharyngeal Space Benign Mixed Tumor

Christine M Glastonbury, MBBS

Key Facts

Terminology

 Synonyms: Pleomorphic adenoma, PPS

 Note: Surgeons often describe lesions as parapharyngeal whether arising in PPS, parotid deep lobe, PMS, or pterygoid muscles

Imaging

 Rounded, well-defined lesion within PPS fat

o Distinct from parotid deep lobe

 Well-defined, rounded lesion when small

 More lobulated when larger

 Marked T2 hyperintensity similar to CSF

Top Differential Diagnoses

 Benign mixed tumor, parotid deep lobe

 Neurogenic tumor, PPS

 Pterygoid venous plexus asymmetry

 2nd branchial cleft cyst

Pathology

 Benign tumor arising in aberrant salivary gland rests

 Solid but often heterogeneous with hemorrhage, cystic degeneration, or necrosis

 Occasional ossific or calcific degeneration

Clinical Issues

 Most asymptomatic, or minimally so, because of deep location and slow growth

 Small lesion usually incidental imaging finding

 Larger lesion may be found at dental/oral exam

Diagnostic Checklist

 Primary parapharyngeal space lesions are uncommon

 MR: T2 signal similar to CSF, but solidly enhances

 Look for fat plane to distinguish from parotid deep lobe benign mixed tumor

(Left) Axial CECT demonstrates a well-defined, slightly lobulated mass within the left parapharyngeal space The

parotid deep lobe

(Left) Coronal T1WI MR shows a well-defined mass to be surrounded by parapharyngeal fat The mass is too small

to have mass effect on adjacent tissues and was incidentally found on brain MR (Right) Axial T2WI FS MR shows homogeneous hyperintensity of a slightly lobulated mass Hyperintensity similar to CSF is typically seen with benign mixed tumors although post-contrast images confirm it to be a solid mass

 Benign tumor arising from aberrant minor salivary gland rests in parapharyngeal space

 Note: Surgeons often describe lesions as parapharyngeal whether arising in PPS, parotid deep lobe,

pharyngeal mucosal, or masticator space

IMAGING

General Features

 Best diagnostic clue

o Rounded, well-defined lesion within PPS fat

 Distinct from parotid deep lobe

o Well-defined, rounded lesion when small

o More lobulated with increasing size

Imaging Recommendations

 Best imaging tool

o Readily detected on CT or MR

o MR allows better characterization & improved delineation from adjacent structures

 Parotid deep lobe, internal carotid artery

o Occasional focal ossification or calcification

Benign Mixed Tumor, Parotid Deep Lobe

 Identical appearance but within parotid deep lobe

Pterygoid Venous Plexus Asymmetry

 Tubular enhancing structures in PPS or medial masticator space

Neurogenic Tumor, PPS

 Well-defined, oval mass

 Intermediate T2, homogeneous CE if small

2nd Branchial Cleft Cyst (BCC)

 Type IV BCC lies within PPS

 Cystic mass abutting lateral pharyngeal wall

PATHOLOGY

General Features

 Etiology

o Benign tumor arising in aberrant salivary gland rests

Gross Pathologic & Surgical Features

 Solid but often heterogeneous with hemorrhage, cystic degeneration, or necrosis

 Occasional ossific or calcific degeneration

Microscopic Features

 As name implies, morphologically diverse

o Epithelial and myoepithelial cells, mesenchymal or stromal elements

CLINICAL ISSUES

Presentation

 Most common signs/symptoms

o Most asymptomatic because of deep location and slow growth

 Small lesion usually incidental imaging finding

 Large lesion may be found at dental/oral exam

o Large mass often has minimal symptoms

 Painless oral swelling or dysphagia Demographics

 Age

o Adults; peak in 5th decade

 Gender

o Slight female predominance

Natural History & Prognosis

 Slow growing; may be asymptomatic even when large

 Uncommonly degenerates to malignant mixed tumor (carcinoma ex-pleomorphic adenoma)

Treatment

 Resection for definitive pathological diagnosis or if large and symptomatic

 Operative tumor cell “spillage” may result in recurrence

DIAGNOSTIC CHECKLIST

Image Interpretation Pearls

 Primary PPS lesions are uncommon

o Should be entirely surrounded by fat

 Look for fat at posterolateral margin to distinguish BMT of PPS from parotid deep lobe lesion

SELECTED REFERENCES

1 Pelaz AC et al: Simultaneous pleomorphic adenomas of the hard palate and parapharyngeal space J Craniofac Surg

Section 3 - Pharyngeal Mucosal Space

Introduction and Overview

Pharyngeal Mucosal Space Overview

> Table of Contents > Part I - Suprahyoid and Infrahyoid Neck > Section 3 - Pharyngeal Mucosal Space > Introduction and Overview > Pharyngeal Mucosal Space Overview

Pharyngeal Mucosal Space Overview

H Ric Harnsberger, MD

Summary Thoughts: Pharyngeal Mucosal Space

The pharyngeal mucosal space (PMS) is a key suprahyoid neck (SHN) space that represents the pharyngeal mucosal surface The PMS has on its nonairway surface the middle layer of deep cervical fascia Important pharyngeal mucosal space contents include the mucosal surface of the pharynx, pharyngeal lymphatic ring (adenoidal, palatine, and lingual tonsils), and submucosal minor salivary glands

An enlarging PMS mass of the palatine tonsil or nasopharyngeal lateral pharyngeal recess displaces the

parapharyngeal space fat laterally Disruption of the mucosal and submucosal landmarks also occurs in PMS masses Important pharyngeal mucosal space malignancies include squamous cell carcinoma (SCCa) arising from the mucosal surface, non-Hodgkin lymphoma (NHL) from the pharyngeal lymphatic ring, and minor salivary gland carcinoma from the normal submucosal minor salivary glands Of these, SCCa is the most frequent and the most important Staging of SCCa primary and nodal disease is one of the most common reasons for imaging studies in the head and neck

The pharyngeal mucosal space is not a true space as it is not enclosed on all sides by fascia It is an imaging construct

to overcome the problems encountered in describing a lesion of the pharynx as nasopharyngeal, oropharyngeal, and hypopharyngeal These terms, although universally applied to lesions of the pharyngeal surface, do not address the deep tissue component of an invasive PMS mass Describing a lesion as primary to the PMS with extension into the adjacent suprahyoid neck spaces clearly delineates lesion extent in a radiologic report

Imaging Techniques & Indications

Both CECT and enhanced MR can be used to image the pharyngeal mucosal space If tonsillar or peritonsillar abscess is the major clinical concern, CECT of the soft tissues with bone CT of the mandible is a better choice When pharyngeal squamous cell carcinoma tumor staging is requested, enhanced fat-saturated multiplanar MR is the better exam MR

is less affected by dental amalgam artifact than CT as well as visualizes perineural and perivascular tumor spread more readily In larger tumors of the oropharynx and nasopharynx already imaged with MR, the addition of noncontrasted bone CT provides information regarding bone invasion that may be difficult to derive from MR imaging

Imaging Anatomy

The anatomic relationships of the pharyngeal mucosal space and surrounding deep tissue anatomy are extremely important because both PMS malignancy and infection readily spread into these adjacent areas Directly posterior to the PMS is the retropharyngeal space (RPS) The parapharyngeal space (PPS) is lateral to the PMS

Superiorly the pharyngeal mucosal space abuts the skull base along the roof and posterosuperior portion of the nasopharynx This broad abutment with the skull base includes the posterior basisphenoid (sphenoid sinus floor) and the anterior basiocciput (anterior clival margin) The foramen lacerum (cartilaginous floor of the anteromedial petrous ICA canal) is a key area of abutment of the PMS with the skull base Nasopharyngeal carcinoma accesses the

intracranial compartment via the perivascular spread along the ICA beginning at the foramen lacerum

The PMS extends from the roof of the nasopharynx above to the hypopharynx below as a continuous mucosal sheet This mucosal space/surface is subdivided into nasopharyngeal, oropharyngeal, and hypopharyngeal components The PMS is a space with fascia on each deep margin but no superficial fascia With no fascia on the surface of the PMS,

it is not a true fascia-enclosed space In fact it represents a conceptual construct to complete the spatial map of the suprahyoid neck The term pharyngeal mucosal surface functions just as well as pharyngeal mucosal space

The middle layer of deep cervical fascia (ML-DCF) defines the deep margin of the PMS Just below the skull base, the ML-DCF encircles the lateral and posterior margins of the pharyngobasilar fascia (tough aponeurosis connecting the superior constrictor muscle to the skull base) In the more inferior nasopharynx and oropharynx, the ML-DCF resides

on the deep margin of the superior and middle constrictor muscles

Important PMS internal structures include the mucosa, lymphatic ring (of Waldeyer), and minor salivary glands The pharyngeal lymphatic ring is divided into three components: The nasopharyngeal adenoids and the oropharyngeal palatine (faucial) and lingual tonsils (base of tongue) The lymphatic tissue normally declines in volume with age Minor salivary glands are found in the submucosa throughout the pharynx, larynx, and trachea Their highest

concentration is found at the hard-soft palate junction

The nasopharyngeal mucosal space also contains the superior constrictor muscle and the pharyngobasilar fascia Along the posterosuperior margin of the pharyngobasilar fascia there is a notch referred to as the sinus of Morgagni The levator palatini muscle and the distal eustachian tube (torus tubarius) project into the PMS through this notch Approaches to Imaging Issues of the Pharyngeal Mucosal Space

The answer to the question, “What imaging findings define a pharyngeal mucosal space mass?” depends on the area

of the PMS where the mass originates The most common PMS mass arises in the lateral pharyngeal recess of the nasopharynx or in the palatine tonsil of the oropharynx As such it is medial to the PPS, displacing the PPS fat laterally

as it enlarges A PMS mass of the lingual tonsil projects into the posterior sublingual space of the tongue as it enlarges The rare posterior nasopharyngeal or oropharyngeal wall mass pushes posteriorly into the RPS as it grows No matter where in the PMS a mass grows, disruption of the mucosal and submucosal architecture occurs In addition, the growing airway side of the mass projects out into the adjacent PMS airway

Traditionally the pharynx is divided into the nasopharynx, oropharynx, and hypopharynx as a method to describe where on the continual sheet of mucosa a SCCa is found This surface of the pharynx we refer to here as the

pharyngeal mucosal space To unify these two terminologies, it is possible to refer to the nasopharyngeal, P.I(3):3 oropharyngeal, or hypopharyngeal mucosal space It is not helpful to merely refer to a tumor as either of the

oropharynx or found in the oropharyngeal mucosal space The radiologist must also describe what other deep facial spaces are involved by a PMS tumor This requires bringing the other deep facial spaces affected into the radiologic report, including the PPS, MS, parotid space (PS), CS, RPS, and perivertebral space (PVS)

When the PMS lesion is identified on CT or MR imaging, there are a limited number of common diseases to consider

If the patient is imaged to evaluate for possible infection, three lesions may be identified Tonsillar lymphoid

hyperplasia is commonly found in children and young adults, resulting from multiple bouts of tonsillar inflammation Tonsillar inflammation is suggested when enhancing, enlarged tonsils possess “stripes.” Tonsillar abscess is diagnosed when focal rimenhancing pus collections are seen If the abscess has ruptured from the tonsil into the adjacent PPS, RPS, or masticator space (MS), the term peritonsillar abscess may be used

If the PMS lesion lacks a clinical infectious context but has invasive imaging features, a limited group of malignant tumors must be considered Squamous cell carcinoma is by far the most common malignancy of the PMS with non-Hodgkin lymphoma (NHL), next in frequency followed by minor salivary gland carcinoma These neoplasms arise from the normal structures found within the PMS

 Mucosa → squamous cell carcinoma

 Pharyngeal lymphatic ring → NHL

 Minor salivary glands → Minor salivary gland carcinoma

 Notochordal remnant → extraosseous chordoma

 Constrictor and levator palatini muscles → rhabdomyosarcoma

The most common interpretation pitfall associated with the PMS occurs when the radiologist overcalls large adenoidal tonsillar tissue as tumor Recurrent tonsillar inflammation in the young may lead to disturbingly prominent tonsillar hyperplasia on CT or MR imaging If the prominent lymphatic tissue in the PMS has no invasive deep margins,

demonstrates “inflammatory septa,” and is found in a patient under 20 years of age, lymphoid hyperplasia is the most likely explanation

A second common interpretation pitfall occurs when the lateral pharyngeal recess is asymmetric either because of retained secretions, retention cysts, or unevenly distributed adenoidal tissue Suggesting nasopharyngeal carcinoma

in this setting creates great patient and physician consternation Suggesting normal asymmetry and recommending clinical inspection usually suffice to clear the nasopharynx of significant pathology

Clinical Implications

Remember that the referring clinician can usually directly visualize a lesion of the PMS Lesions of the lateral

pharyngeal recess of the nasopharynx may be the exception to this rule In the case of SCCa, the appearance of the mucosal lesion is often diagnostic Knowing what the physical examination of the pharynx shows at the time of rendering your radiologic report allows for a richly detailed and highly relevant interpretation

If the requisition requests a staging CT or MR of a SCCa of the PMS, the report should comment on both the primary tumor (T) and nodal (N) stage The 2010 AJCC staging manual defining the T and N stages of each of the subsites of the pharynx is an important reference for the radiologist doing this type of work Familiarity with the routes of spread of SCCa of the PMS by primary site and subsite also permit directed radiologic reports to be rendered

Nasopharyngeal carcinoma (NPCa), because of its proximity to the skull base, spreads early into the intracranial compartment The middle layer of deep cervical fascia and the pharyngobasilar fascia direct NPCa cephalad to invade directly into the upper clivus, floor of the sphenoid sinuses, and the foramen lacerum When the tumor invades through the foramen lacerum it accesses the anteromedial internal carotid artery Perivascular spread takes it into the

1 Parker GD et al: The pharyngeal mucosal space Semin Ultrasound CT MR 11(6):460-75, 1990

Tables

Differential Diagnosis of Pharyngeal Mucosal

Space

Pseudolesions Malignant tumor

Asymmetric tonsillar tissue

Palatine tonsil SCCa

Inflammatory lesions

Lingual tonsil SCCa

Infectious lesions Tornwaldt cyst

Image Gallery

(Top) Axial graphic of the nasopharyngeal mucosal space (in blue) shows that the superior pharyngeal constrictor, levator veli palatini muscles, and the cartilaginous eustachian tube ending (torus tubarius) are within the space The levator veli palatini and eustachian tube access the pharyngeal mucosal space via the sinus of Morgagni in the upper margin of the pharyngobasilar fascia The middle layer of deep cervical fascia provides a deep margin to the space The retropharyngeal space is behind and the parapharyngeal space is lateral to the pharyngeal mucosal space (Bottom) Axial graphic of the oropharyngeal mucosal space (in blue) viewed from above reveals that the superior pharyngeal constrictor and the tonsillar pillars along with the palatine & lingual tonsils are all occupants of this space The middle layer of deep cervical fascia provides a deep margin to the space The retropharyngeal space is behind & the parapharyngeal space is lateral to the pharyngeal mucosal space.

P.I(3):5

(Left) Axial T2WI MR shows the pharyngeal mucosal space at the level of the nasopharynx Notice the opening to the eustachian tube and torus tubarius The lateral pharyngeal recess is collapsed with the 2 mucosal surfaces touching each other (Right) Axial T2WI MR through the mid-oropharynx reveals the palatine tonsil as the main occupant of the PMS The superior constrictor muscle and the palatopharyngeus muscles are visible.

(Left) Coronal graphic shows nasopharyngeal and oropharyngeal mucosal space Note the middle layer of deep cervical fascia defining the lateral margin of the nasopharyngeal PMS and the oropharyngeal PMS The parapharyngeal spaces are paired fatty spaces lateral to the pharyngeal mucosal space (Right) Coronal enhanced fat-saturated T1WI MR reveals the normal enhancing sheet of mucosa Notice the torus tubarius (cartilaginous eustachian tube) & lateral pharyngeal recesses

(Left) Skull base graphic viewed from below highlights area of PMS abutment (blue) Note posterior basisphenoid & clival basiocciput both are involved Foramen lacerum are both within abutment area (Right) Axial graphic through the nasopharynx depicts a generic PMS mass The lesion projects into the nasopharyngeal airway as well

as pushes from medial to lateral on the adjacent parapharyngeal space Notice the close proximity of the nasopharyngeal carotid space with CN9-12

 Homogeneously high signal on T2 with no deep extension into surrounding structures

 May have minimal enhancement of cyst wall possible

Top Differential Diagnoses

 Adenoidal inflammation

 Retention cyst, pharyngeal mucosal space

 Benign mixed tumor, pharyngeal mucosal space

 Most common lesion of nasopharyngeal mucosal space occurring in 4% at autopsy

 Seen on ˜ 5% of routine brain MR

 Usually asymptomatic and incidental

 Rarely, chronically infected large cyst (> 2 cm) causes periodic halitosis and unpleasant taste in mouth Diagnostic Checklist

 If invasion into prevertebral muscles, think nasopharyngeal carcinoma

(Left) Sagittal T1WI MR in a patient with a medium-sized Tornwaldt cyst The cyst is slightly hyperintense

presumably due to increased protein content Subtle internal septation is present (Right) Coronal enhanced saturated MR through the pituitary gland in the same patient reveals the nonenhancing Tornwaldt cyst within the otherwise enhancing nasopharyngeal mucosal space

fat-(Left) Axial T2WI MR reveals a Tornwaldt cyst in the midline nasopharyngeal mucosal space that is hypointense due to proteinaceous contents Tornwaldt cysts are often high signal when water content is higher Note the discrete plane between cyst and deep muscles indicating its mucosal surface location (Right) Axial T1WI C+ fat-saturated MR demonstrates a classic small nonenhancing Tornwaldt cyst The mucosal surface enhances and is seen as a thin white line

 Best diagnostic clue

o Midline, well-circumscribed NP cyst on posterior wall between prevertebral muscles

o Homogeneously high signal intensity NP cyst with no deep extension into surrounding structures

o Lower T2 signal possible with high protein content

 T1WI C+

o May have minimal enhancement of cyst wall

Imaging Recommendations

 Best imaging tool

o Easily seen & diagnosed on T2 MR images

DIFFERENTIAL DIAGNOSIS

Adenoidal Inflammation

 T2 high signal diffuse soft tissue filling nasopharyngeal mucosal space

Retention Cyst, Pharyngeal Mucosal Space

 Often multiple, lateral pharyngeal recess lesions hyperintense on T2

Benign Mixed Tumor, Pharyngeal Mucosal Space

 Rare, well-circumscribed enhancing mass

Nasopharyngeal Carcinoma

 Invasive nasopharyngeal mucosal space mass

 T2 intermediate signal, diffuse enhancement except in necrotic portions

Gross Pathologic & Surgical Features

 Smooth, translucent cyst if uninfected

 Thick-walled if prior infection

Microscopic Features

 Cyst lining: Respiratory epithelium, little or no lymphoid tissue is seen in cyst wall

 Cyst fluid: Usually with high protein concentration

CLINICAL ISSUES

Presentation

 Most common signs/symptoms

o Rarely symptomatic

 Tornwaldt syndrome (rare)

o Chronically infected large cyst (> 2 cm)

o Causes periodic halitosis, unpleasant taste

Demographics

 Age

o Most common in young adults

Natural History & Prognosis

 Incidental finding on MR with no clinical significance

Treatment

 Asymptomatic cysts require no treatment

 Chronically infected, painful lesions treated with excision

DIAGNOSTIC CHECKLIST

Consider

 TC if high signal intensity midline NP cyst on T2 MR

Image Interpretation Pearls

 TC on routine brain MR is of no clinical significance

2 Ikushima I et al: MR imaging of Tornwaldt's cysts AJR Am J Roentgenol 172(6):1663-5, 1999

3 Ford WJ et al: Thornwaldt cyst: an incidental MR diagnosis AJNR Am J Neuroradiol 8(5):922-3, 1987

Infectious and Inflammatory Lesions

Retention Cyst of Pharyngeal Mucosal Space

> Table of Contents > Part I - Suprahyoid and Infrahyoid Neck > Section 3 - Pharyngeal Mucosal Space > Infectious and Inflammatory Lesions > Retention Cyst of Pharyngeal Mucosal Space

Retention Cyst of Pharyngeal Mucosal Space

Patricia A Hudgins, MD

Key Facts

Terminology

 Retention cyst (RC) of pharyngeal mucosal space (PMS)

 Synonyms: Post-inflammatory cyst, tonsillar cyst

 RC: Benign, asymptomatic PMS cyst

Imaging

 RC of PMS in nasopharynx or oropharynx

o Usually < 1 cm

o Smooth, well-circumscribed, round or ovoid

o Pear-shaped when in lateral pharyngeal recess nasopharynx

o Discrete plane between cyst and underlying constrictor muscles

 Simple cyst in PMS on CT or MR

o T2 MR: Homogeneously hyperintense mucosal cyst

o CT or MR: No significant enhancement in wall

Top Differential Diagnoses

 Thyroglossal duct cyst at foramen cecum

 Tornwaldt cyst

 PMS benign mixed tumor

 Congenital vallecular cyst

Clinical Issues

 Incidental PMS lesion usually found on lowest images of routine brain MR

 Cyst in lateral pharyngeal recess may obstruct eustachian tube with middle ear-mastoid fluid

 Common incidental lesion found on brain or C-spine MR imaging

Diagnostic Checklist

 Important to recognize PMS RC as benign “leave me alone” lesion

(Left) Sagittal pre-contrast T1WI MR shows characteristic smooth retention cyst in the lateral pharyngeal recess This lesion mimics a Tornwaldt cyst, but the axial images showed the cyst was paramedian (Right) Axial pre-contrast T1WI MR in the same patient shows the characteristic pear-shaped retention cyst in the lateral pharyngeal recess Note the high signal within the cyst suggesting that cyst contents are either hemorrhagic or proteinaceous.

(Left) Axial T2WI MR shows bilateral nasopharyngeal retention cysts , larger on the right Note that the small left retention cyst is septated (Right) Axial CECT at base of tongue level in an adult reveals a right vallecular retention cyst The left vallecula is partially filled with enhancing lingual tonsillar tissue A foramen cecum level thyroglossal duct cyst would be more midline and not fill the vallecula This lesion is fundamentally different from the congenital vallecular cyst of the newborn

o Simple cyst in PMS on CT or MR

 Location

o RC of PMS in nasopharynx & oropharynx

o Lateral nasopharyngeal recess common but can occur anywhere on PMS surface

 Size

o Usually < 1 cm

o Occasionally very large, > 1 cm

 Morphology

o Smooth, well-circumscribed, round or ovoid

 Pear-shaped when in lateral pharyngeal recess nasopharynx

o Usually unilocular but occasionally multiple or septated

o Difficult to detect when fluid-filled & isointense to muscle

o Often slightly hyperintense to muscle due to proteinaceous contents

 T2WI

o Homogeneously hyperintense superficial mucosal cyst

o Discrete plane between cyst and underlying constrictor muscles

Thyroglossal Duct Cyst, Foramen Cecum

 Benign embryologic remnant cyst of thyroglossal duct occurring at foramen cecum

Tornwaldt Cyst

 Benign embryologic notochordal remnant in midline nasopharyngeal mucosal space

Benign Mixed Tumor, PMS

 Solid, homogeneously enhancing PMS lesion

Congenital Vallecular Cyst

 Congenital cyst of vallecula found in newborns

PATHOLOGY

General Features

 Etiology

o Post-inflammatory in origin

Gross Pathologic & Surgical Features

 Soft discrete cyst laying on mucosal surface of nasopharynx or oropharynx

Microscopic Features

 Epithelial-lined cyst filled with serous fluid

 Rare cyst contains old blood products or proteinaceous fluid

CLINICAL ISSUES

Presentation

 Most common signs/symptoms

o Incidental PMS lesion usually found on lowest images of routine brain MR

o Cyst in lateral pharyngeal recess may obstruct eustachian tube with middle ear-mastoid fluid

o Rare large cyst may present with dysphagia

Demographics

 Age

o Usually found in adults

 Epidemiology

o Common incidental lesion found on brain or cervical spine MR imaging

Natural History & Prognosis

 Incidental finding with no progression to symptoms

Treatment

 Rarely, large symptomatic cysts may be surgically excised

DIAGNOSTIC CHECKLIST

Consider

 If cyst in midline nasopharynx: Tornwaldt cyst, not retention cyst

Image Interpretation Pearls

 Important to recognize PMS RC as it is benign “leave me alone” lesion

 Bilateral > unilateral tonsillar enlargement with variable density/intensity/enhancement

 CECT to distinguish acute tonsillitis from peritonsillar/tonsillar abscess (PTA/TA)

o Well-formed capsule and homogeneous internal hypodensity in PTA/TA

 Striated pattern of internal enhancement (“tiger stripe” sign) relatively specific for nonsuppurative tonsillitis

 Reactive adenopathy common

Top Differential Diagnoses

 Tonsillar/peritonsillar abscess

 Prominent/asymmetric tonsillar tissue

 Palatine tonsil squamous cell carcinoma

 Pharyngeal mucosal space non-Hodgkin lymphoma

Pathology

 Most commonly secondary to respiratory virus

 30-40% bacterial: Group A β-hemolytic streptococci (GABHS) most common

Clinical Issues

 Children and young adults

o > 6 million office visits/year by children < 15 years

Diagnostic Checklist

 Striated pattern of internal enhancement, absence of well-defined capsule help rule out PTA/TA