Cavernous malformations, or cavernomas, are small vascular abnormalities not infrequently found in the brain and brain stem. A cavernous malformation is a sack like structure with fragile walls and blood flow within them can be very slow or still. They may be incidental findings, but do carry a small chance of bleeding, and depending on the location may cause seizures. Brainstem cavernomas have higher rates of bleeding, and cavernomas that have previously bled are more likely to have recurrent bleeding. Surgical resection is uncommon unless the lesion is symptomatic and accessible.

SWI sequence brain MRI (blood sensitive). Some people have many, many cavernomas – usually due to a mutation in the KRIT1 or CCM gene. In this case patients may present at a young age and cavernomas may be familial.
T2W Brain MRI, green arrow shows cavernoma

Cavernomas are often described as looking like ‘popcorn’ due to the lobulated appearance on MRI.

Another important aspect of cavernomas – due to the slow blood flow, they are not seen on angiography, despite being vascular anomalies.