Germinoma U tế bào mầm nội sọ

• The usual location of intracranial germinoma is in the midline areas such as the pineal and suprasellar regions.. • Ectopic germinomas, which are tumors arising from midline areas, pri

Intracranial Germinoma

• Intracranial germinomas are a type of germ   cell tumor, and are predominantly seen in

pediatric populations They account for 3-5%

of pediatric intracranial tumors but only 1% of intracranial tumors in adults

0.4-• Germinomas are tumors of young patients

with a peak incidence of 10-12 years of age

(90% of patients being younger than 20 at the time of diagnosis). 

• There is a marked male predominance with a M:F of ~13:1

• They are the most common 

tumor of the pineal region  

• The usual location of intracranial germinoma is in the

midline areas such as the pineal and suprasellar regions.

• Ectopic germinomas, which are tumors arising from midline areas, primarily the basal ganglia and thalamus, only constitute 5% to 10% of all intracranial germinomas 

off-•  Other possible sites of involvement are the third

ventricle, lateral and fourth ventricles and on occasion, the tumor is widespread at presentation and it is difficult

to determine the precise primary site

Clinical presentation

• Presentation depends on location:

• compression of the  tectal plate leading to    

obstructive hydrocephalus   and   Parinaud

syndrome

• involvement of the  pituitary infundibulum   leads

to  diabetes insipidus (most common),  

compression or signs of intracranial

hypertension

Radiographic features

• Germinomas are soft tissue density, enhancing masses When present in the pineal region

they appear to "engulf" the normal pineal

tissue and can have associated central

calcifcation, in contrast to pineocytomas,

and  pineoblastomas   which are described as

"exploding" the foci of calcifcation Cystic

components are commonly found in up to

45% of cases.

A large lobulated mass is centered on the pineal gland, engulfng the pineal calcifation It is somewhat hyperdense compared to adjacent brain

A further smaller mass is seen in the floor of the third ventricle The midbrain is distorted,

compressed and demonstrates low density suggestive of edema Obstructive hydrocephalus is

present. 

MRI demonstrates a soft tissue mass, typically ovoid or lobulated in contour, engulfng the calcifed pineal gland with the following signal characteristics: 

• T1: isointense or slightly hyperintense to adjacent brain  

• T2

– isointense or slightly hyperintense to adjacent brain

– may have areas of cyst formation 

– may have areas of hemorrhage (low signal)

– have a predilection for invading adjacent brain (edema)

– central calcifcation appears low signal (engulfed pineal gland)

• T1 C+ (Gd): vivid and homogeneous  

• The vast majority of germinomas demonstrated predominantly restricted (36%) or normal (55%) diffusion.

A large enhancing mass is centered on the pineal region It is heterogeneous with areas of cystic change There is marked compression of

the tectum with resulting obstructive

hydrocephalus A little surrounding edema is

also present. 

There is a T1 isointense to brain, T2 hyperintense mass flling the inferior recesses of the third ventricle and extending

down along the infundibulum into the pituitary fossa It

demonstrates intermediate relatively homogeneous contrast enhancement The pineal gland, is a little bulky and

demonstrates similar signal intensity and enhancement. The mass elevates and compresses the optic chiasm and results in increased signal in the optic tracts bilaterally

The tumor is located in left basal ganglion displaying relative well-defned margin

on T2WI

The tumor with ill-defned margin is located in right temporal lobe, basal ganglion, internal

capsule and thalamus with heterogeneous enhancement on post-contrast T1WI

Non-contrast-enhanced CT head at initial presentation.There is

transependymal fluid shift with enlargement of the lateral and third ventricles with nodular densities prominent in the occipital and anterior

horns bilaterally

Post-contrast axial and sagittal MRI sequences with neuronavigation protocol

at diagnosis.There is diffuse involvement of the lateral and third ventricles, the

suprasellar and pineal regions, and the aqueduct with resultant

ventriculomegaly

Differential diagnosis

• Pineal region mass

• pineal cyst (most common benign pineal  

• Pituitary region masses

Treatment and prognosis

• Complete surgical removal does not play a major role in the management of these highly vascular tumors Histological diagnosis following a craniotomy or endoscopic biopsy is recommended for the majority of patients

• Radiation alone used in relatively high doses and volumes usually provides a curative option for the majority of

patients but the late effects of therapy

• The current proposed treatment in a current Children's

Oncology Group protocol for CNS germinomas consists of four cycles of chemotherapy followed by lower dose whole ventricular radiation therapy

Treatment and prognosis

• Overall the prognosis is good, with over 90% 5-year survival with chemotherapy and

radiotherapy.

• Germinomas are potentially malignant in

behavior and both infltrate normal brain

tissue as well as spread throughout the CNS

• https://www.ncbi.nlm.nih.gov/pmc/articles/ PMC5207546/

• https://radiopaedia.org/articles/central-ner vous-system-germinoma

• https://link.springer.com/article/10.1007/s0 0381-010-1247-2

• https://www.ncbi.nlm.nih.gov/pmc/articles/ PMC6088312