Diagnosis: cerebral cavernous malformation

Terminology

• represents a benign vascular hamartoma
  • contains masses of closely apposed immature blood vessels ("caverns"), no neural tissue
  • intralesional hemorrhages of different ages
• exhibit a range of dynamic behavior (enlargement, regression, de novo formation)

Imaging

• vary from microscopic to giant (> 6 cm)
• locules of variable size contain blood products at different stages of evolution
  • variable appearance depending on hemorrhage/stage
• Zabramski classification
  • type 1 = subacute hemorrhage (hyperintense on T1WI; hyper-/hypointense on T2WI)
  • type 2 = mixed signal intensity on T1, T2WI with degrading hemorrhage of various ages (classic "popcorn ball" lesion)
  • type 3 = chronic hemorrhage (hypo- to iso on T1, T2WI)
  • type 4 = punctate microhemorrhages ("black dots"), poorly seen except on T2* sequences
• angiography is usually normal ("angiographically occult vascular malformation") unless the lesion is extradural

Differential considerations include:

• arteriovenous malformation
• hemorrhagic neoplasm
• calcified neoplasm
• hypertensive microbleeds
• cerebral amyloid angiopathy