Hemangioblastoma u nguyên bào mạch máu

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 Epidemiology • • • • Typically occur in young to middle-aged adults, peak incidence at around 30-60 years of age, earlier in patents with VHL Account for only 1-2.5% of all intracranial tumors and approximately 10% of all posterior fossa 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 Clinical presentation • • • • • • headaches: 70%  hydrocephalus and symptoms of raised intracranial pressure: 50 %  cerebellar dysfuncton: ~50-60%  altered mental state: 10% Polycythemia Acute:  signifcant hemorrhage is uncommon and tends to be seen in larger tumors (>1.5 cm) Location • intracranial: 87-97%  – 95% in the posterior fossa • • • • • 85% in cerebellar hemisphere 10% in the cerebellar vermis 5% medulla only rarely they extend beyond the cerebellum into the cerebellopontne angle – 5% supratentorial (typically in the optc radiatons) spinal: 3-13%  Radiographic features • Typically hemangioblastomas (60% of cases) are sharply demarcated homogeneous masses composed of a cyst with non-enhancing walls, except for a mural nodule which vividly enhances and ofen has prominent serpentne  flow voids  • In the remaining 40%, the tumor is solid with no cystc cavity CT • the mural nodule is isodense to the brain on non-contrast scans with fluid density surrounding cyst • • • postcontrast intense homogeneous enhancement of the mural nodule   the cyst walls not usually enhance 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 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 ependymoma 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 Medulloblastoma • – – – common in childhood much more solid restricted diffusion Overall the vast majority (94%) of medulloblastomas arise in the cerebellum and the majority of these, from the vermis (75%) They tend to protrude into the  fourth ventricle from its roof, and may even grow directly into the  brainstem • ependymoma – usually arises from the floor of the th  ventricle – typically squeezes out the foramen of Luschka – does not usually cause as much diffusion restricton Conclusion • • • • • • Intracranial hemangioblastoma: WHO grade 30-60 years 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 ...Intracranial hemangioblastoma • Hemangioblastomas are tumors of vascular origin and occur both sporadically and in patents... 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... cases  • – fluid-flled cyst, similar to CSF MR perfusion imaging: high rCBV ratos Supratentorial hemangioblastomas are usually solid and are mostly located in the frontal lobe  Characteristc imaging