Hemangioblastoma u nguyên bào mạch máu

• Hemangioblastomas are tumors of vascular origin and occur both sporadically and in patents with von Hippel Lindau disease.. Radiographic featuresa mural nodule which vividly enhances

Intracranial hemangioblastoma

• Hemangioblastomas are tumors of vascular origin and occur both sporadically  and in patents with von Hippel Lindau disease They are WHO grade 1 tumors

• Slight male predilecton in adults: M: F rato of 1.3-2.6:1

• Sporadic cases make up approximately 75-80%, remainder being found in patents with VHL  

• only rarely do they extend beyond the cerebellum into the cerebellopontne angle

– 5% supratentorial (typically in the optc radiatons)

Radiographic features

a mural nodule which vividly enhances and ofen has prominent serpentne 

flow voids 

• the mural nodule is isodense to the brain on non-contrast scans with fluid density surrounding cyst

• calcifcaton is not a feature

A large lef cerebellar irregular mass lesion with necrotc core and irregular thick enhancing margins,

compressing and involving the lef side of the 4th ventricle

• T1

– hypointense to isointense mural nodule

– CSF signal cyst content

– mural nodule vividly enhances 

– cyst wall does not enhance 

• T2

– hyperintense mural nodule

– flow voids due to enlarged vessels may be evident especially at the periphery of the   cyst, seen in 60-70% of cases 

– fluid-flled cyst, similar to CSF

Supratentorial hemangioblastomas are usually solid and are mostly located in the frontal lobe .

Characteristc imaging fndings include bright signal on T2 WI, prominent flow voids, and vivid post-contrast enhancement Also, peritumoral edema

is usually observed.

Differental diagnosis includes angiomatous meningioma, hemangiopericytoma, and metastatc renal cell carcinoma.

Treatment and prognosis

• Surgical resecton is usually curatve, and with large lesions may be made easier

by preoperatve embolizaton Adjuvant radiotherapy may be used in patents with incomplete resectons Recurrence can be seen in up to 25% of patents

Differential diagnosis

• brain metastases

• medulloblastoma

• Solid components of hemangioblastoma tended to show lower intensity on DWI compared with that of brain metastases and the tendency became stronger on DWI at high b values.

• the ADC values of brain metastases were statstcally lower than those of hemangioblastomas (P < 0.0001 in ADCMIN,

ADCMEAN, and ADCMAX; Mann-Whitney U test) With the cutoff value at 0.6x10-3 mm2 /second, the positve predictve value

of ADCMIN at b = 1000 was 89.3% and that of ADCMIN at b = 4000 was 100% (logistc regression analysis).

• a rCBV cutoff value of 8.0 showed the highest accuracy for differentatng

hemangioblastoma from metastasis

• a rCBV > 8.0 showed 85.7 % sensitvity, 93.3 % specifcity, and 90.9 % accuracy for differentatng hemangioblastoma from metastatc brain tumor

fourth ventricle   from its roof, and may even grow directly into the 

brainstem

• 95% in the posterior fossa: cerebellar hemisphere

• cyst with non-enhancing walls, mural nodule vividly enhances, flow void  

• Differental diagnosis: Metastasis, other posterior fossa tumor: medulloblastoma, astrocytoma, ependymoma