IS case 455: Cavernous angioma
Imaging Sciences URMC 2010
Publication Date: 2010-08-30
History
Patient is a 25-year-old male with no significant past medical history presenting with new onset of seizures.
Findings
On CT, there was an 1.9 x 1.3 cm high attenuation lesion in the right frontal lobe, with areas of calcifications. The surrounding parenchyma was normal, without signs of edema or mass effect. On MR, there was heterogeneously high signal intensity on T1 and T2 images in the right frontal lobe. On T2WI images there was a ring of low attenuation surrounding the lesion.
Diagnosis
Discussion
Cavernous angiomas are benign vascular hamartomas characterized by closely opposed dilated blood vessels with an absence of neuronal tissue within the lesion. Cavernous angiomas or cavernomas have an approximate prevalence of 0.5% and occur as solitary sporadic lesions in 75% of cases, with 10-30% being familial. They most commonly occur in the frontal and temporal regions, with approximately 90% being supratentoral. Cavernomas can exhibit a wide range of dynamic behaviors, such as enlargement, regression and de novo formation. The peak presentation of cavernomas is ages 40-60 without gender predilection. The most common presentation of cavernomas are: seizure (50%), neurological deficit (25%) and asymptomatic (20%). Complications caused by cavernomas are secondary to hemorrhage and less commonly mass effect. The risk of clinically significant hemorrhage is not well established, but it is estimated to be 0.2-2% per lesion per year. This risk is increased in patients with established prior hemorrhage. Although most cavernous angiomas can simply be followed up over time, surgical removal is an option in lesions causing significant morbidity.
On CT cavernomas appear as well circumscribed ovoid hyperdense lesions, which most commonly are less than 0.5-3 cm in size. There is no surrounding edema, unless there is acute hemorrhage, with the surrounding brain appearing normal. 40-60% contain calcifications which will be seen as high attenuation scattered throughout the lesion. Cavernomas commonly display little to no enhancement on contrast enhanced CTs. The specificity and sensitivity of CT is less than that of MR, making MR the study of choice for diagnosing cavernomas. On T1WIs, cavernomas have a characteristic "popcorn ball" appearance, with mixed hyper and hypo-intense blood locules. On T2WIs the popcorn-like lesion is the most common presentation, with a mixed signal core and hypointense hemosiderin ring surrounding the lesion. There may be fluid-fluid levels secondary to locules of blood, within the cavernoma. The preferred sequence for cavernomas is T2 GRE because it can detect smaller or multiple lesions that may not be visible on standard spin-echo images. On T2 GRE sequences the cavernoma will display a characteristic blooming, secondary to the peripheral rim of hemosiderin.
References
- Harrigan MR, Deveikis JP. Handbook of Cerebrovascular Disease and Neurointerventional Technique. Humana Press, 2009.
- Hoang TA, Hasso AN. Intracranial vascular malformations. Neuroimaging Clin N Am. 1994 Nov;4(4):823-47. PMID: 7858922
- Ide C, De Coene B, Baudrez V. MR features of cavernous angioma. JBR-BTR. Dec 2000;83(6):320. PMID: 11210687
- Osborn AG. Intracranial vascular malformations. In: Diagnostic Neuroradiology. Mosby-Year Book;1994:284, 311-4.
4 images
