= benign autosomal dominant tumor of vascular origin

Incidence: 1–2.5% of all intracranial neoplasms; most common primary infratentorial neoplasm in adults (10% of posterior fossa tumors)

Age:

1. adulthood (>80%): 20–50 years, average age of 33 years; M >F
2. childhood (<20%): in von Hippel-Lindau disease (10–20%); girls

Associated with:

1. von Hippel-Lindau disease (in 20%), may have multiple hemangioblastomas (only 20% of patients show other stigmata)
2. pheochromocytoma (often familial)
3. syringomyelia
4. spinal cord hemangioblastomas

• headaches, ataxia, nausea, vomiting
• erythrocythemia in 20% (tumor elaborates stimulant)

Location: paravermian cerebellar hemisphere (85%) >spinal cord >cerebral hemisphere / brainstem; multiple lesions in 10%

• solid (⅓) / cystic / cystic with mural nodule
• solid portion often intensely hemorrhagic
• almost never calcifies

CT:

• cystic sharply marginated mass of CSF-density (⅔)
• peripheral mural nodule with homogeneous enhancement (50%)
• occasionally solid with intense homogeneous enhancement

MR:

• well-demarcated tumor mass moderately hypointense on T1WI + T2WI
• hyperintense areas on T1WI (= hemorrhage)
• hypointense areas on T1WI + hyperintense areas on T2WI (= cyst formation)
• intralesional vermiform areas of signal dropout (= high-velocity blood flow)
• heterogeneous enhancement on Gd-DTPA with nonenhancing foci of cyst formation + calcification + rapidly flowing blood
• perilesional Gd-DTPA enhancing areas of slow-flowing blood vessels feeding and draining the tumor
• peripheral hyperintense rim on T2WI (= edema)

Angio:

• densely stained tumor nidus within cyst (“contrast loading”)
• staining of entire rim of cyst
• draining vein

Prognosis:>85% postsurgical 5-year survival rate

DDx:

1. Cystic astrocytoma (>5 cm in size, calcifications, larger nodule, thick-walled lesion, no angiographic contrast blush of mural nodule, no erythrocythemia)
2. Arachnoid cyst (if mural nodule not visualized)
3. Metastasis (more surrounding edema)