What it is
Cavernous malformations (also called cavernomas or cavernous angiomas) are clusters of enlarged, abnormally formed blood vessels packed tightly together without normal brain tissue between them. They do not have a significant arterial supply, which distinguishes them from arteriovenous malformations. On MRI they have a characteristic "popcorn" appearance from blood products in various stages of breakdown.
They can be sporadic or familial — a genetic form (familial cerebral cavernous malformation) can produce multiple lesions across generations.
Behavior and risk
Cavernous malformations bleed at low rates — roughly 0.5–2% per year for most lesions. Each bleed is usually small and self-limited, but repeat bleeds can accumulate neurological injury over time. The risk of significant bleeding is higher for lesions in the brainstem, where even a small hemorrhage can cause serious deficits.
When surgery is considered
Surgery is considered when:
- There has been at least one symptomatic hemorrhage and the lesion is in an accessible location
- Progressive neurological deficit is attributable to the lesion
- Seizures are medically refractory and likely driven by the malformation
- The lesion is in a high-risk location (brainstem) where a second bleed could be devastating
Incidental cavernous malformations without symptoms or hemorrhage are generally observed. Stereotactic radiosurgery has a limited and debated role and is typically reserved for surgically inaccessible lesions with significant hemorrhage history.