1. Cerebellar Hemangioblastoma

• tumors are usually well circumscribed and may be solid or cystic
• microscopically, present as large numbers of thin-walled, closely packed blood vessels
• usually found in the paramedial aspect and associated with prominent vessels but any cerebellar region affected

2. Retinal Hemangioblastoma (or angiomata)

• characterized by small, raised masses of retinal tissue composed of thin-walled capillaries that are fed by large and tortuous arterioles and venules
• may be divided into 3 categories
• by ophthalmoscopic examination, may appear as a dilated artery leading from the disk to a peripheral tumor with an engorged vein
• usually observed in the retinal periphery (so vision unaffected)

1. CNS Hemangioblastomas

• make up 2% of all brain tumors
• make up 7-10% of all posterior fossae tumors

2. Cerebellar Hemangioblastomas (83%)

• mean age of onset is 32 yrs; before age 15 is rare
• may present with posterior fossae signs/symptoms
  • obstructive hydrocephalus (with elevated intracranial pressure)
  • cerebellar signs (ataxia, nystagmus)
  • coning
• associated with polycythemia in 10-50% of patients
• all children presenting with cerebellar hemangioblastomas have VHL

3. Other Sites

1. Retinal Hemangioblastomas (46%)

• may appear as early as the 1st decade but usually in 2nd (before the presentation of cerebellar hemangioblastomas)
• may present:
  • vision unaffected (if tumor in periphery)
  • visual impairment with:
    • macular involvement
    • intraocular hemorrhage
    • retinal detachment secondary to exudation
  • may be multiple and bilateral
  • no sex predilection

1. Visceral Cysts

• tend to progress and become apparent during adult life
• pancreatic (72%)
• renal (59%)
• hepatic (17%)
• epididymis (7%)

2. Other Tumors

Note: the clinical features vary widely from benign to devastating