Cavernous malformation

  • Benign vascular hamartoma
  • Imaging shows loculles of blood at different stages of evolution
  • Classic MR appearance is popcorn ball appearance with complete hypointense hemosiderin rim on T2 MR
  • CT is usually negative but may see calcification
  • Unlikely to enhance or show up on CTA unless mixed with another lesion
  • T1 popcorn ball mixed hyper-/hypointense, blood-containing locules
  • T2 Reticulated, popcorn-like lesion is most typical, Mixed signal core, complete hypointense hemosiderin rim
  • Best is T2 SWI, will see prominent susceptibility effect (hypointense blooming)
  • FLAIR may see surrounding edema
  • DSA usually normal
  • Zabramski calssification
    • Type 1 = subacute hemorrhage (may obscure CM)
    • Type 2 = mixed signal intensity on T1, T2 MR "popcorn ball")
    • Type 3 = chronic hemorrhage (hypo-/isointense on T1, T2 MR)
    • Type 4 = punctate microhemorrhages (blooming "dots" on T2* MR
  • Most commonly associated with DVAs
  • Most typical presentation is seizure
  • 2/3 occur as solitary sporadic lesions while 1/3 are multiple familial (more common in Mexican descent with founder mutation in KRIT1)
  • Removed with microsurgery (or gamma knife if difficult location)
  • Important to preserve venous draining if associated with DVA