What is a cavernoma?

What is a Cavernoma?

A cavernoma (cavernous malformation) is a congenital low-flow vascular malformation consisting of abnormally dilated, thin-walled sinusoidal blood-filled spaces lined with endothelium, without normal intervening brain tissue, arteriovenous shunting, or enlarged feeding arteries. 1

Structural Characteristics

• Cavernomas are comprised of multiple sinusoidal endothelial spaces containing venous blood with intravascular or intervascular calcifications, lacking normal brain parenchyma between the vascular channels. 1
• The feeding arteries and draining veins remain normal caliber with no arteriovenous shunting, which explains why bleeding tends to be less dramatic than with arteriovenous malformations. 1
• These lesions grow over time through repeated hemorrhages followed by tissue fibrosis and calcification, not through true vascular proliferation. 1

Epidemiology and Genetics

• Cavernomas occur in approximately 0.4-0.5% of the general population, affecting males and females equally across all age groups. 2
• Multiple cavernomas are present in 13% of sporadic cases and 50% of familial cases. 1
• Three genes have been identified in familial cases: CCM1 (KRIT1) at 7q21-q22, CCM2 (MGC4607) at 7p15-p13, and CCM3 (PDCD10) at 3q25.2-q27, accounting for up to 75% of affected families. 1
• Approximately 9% of cavernomas are associated with prior cranial irradiation. 1

Clinical Presentation

Cavernomas account for approximately 17% of hemorrhagic strokes in children. 1 The clinical manifestations include:

• Hemorrhage is the most serious complication, occurring in 62% of pediatric patients at presentation. 1
• Seizures occur in 35% of children, with or without hemorrhage. 1
• Focal neurological deficits develop depending on lesion location. 1
• Isolated headache may be the presenting symptom. 1
• Approximately 20-26% of cavernomas are discovered incidentally on imaging. 1, 2

Location and Distribution

• 86% of cavernomas are supratentorial and 14% are infratentorial in location. 1
• Deeper lesions (brainstem, basal ganglia, thalamus) carry higher bleeding risk than superficial lesions. 1
• Cavernomas can occur throughout the central nervous system, including the spinal cord and extremely rare locations like the septum pellucidum. 3, 4

Natural History and Hemorrhage Risk

• The annual hemorrhage rate is estimated at 3.3-4.5% for known cavernomas. 1
• After a first hemorrhage, the risk of rebleeding increases to 29.5% over 5 years. 5
• The presence of acute and subacute blood products on imaging increases the likelihood of future hemorrhage. 1
• More deeply situated cavernomas carry higher bleeding risk than superficial lesions. 1

Associated Vascular Anomalies

Approximately 20% of developmental venous anomalies (DVAs) are associated with cavernomas, and most hemorrhages in patients with DVAs are attributed to the associated cavernoma rather than the DVA itself. 1, 6

Diagnostic Imaging

MRI is the imaging study of choice for cavernoma diagnosis and characterization. 1, 7

• The characteristic "bull's-eye" appearance on MRI results from bleeding and residual hemosiderin deposition. 1
• T2-weighted gradient-echo sequences or susceptibility-weighted imaging (SWI) are superior to standard spin-echo imaging for detecting additional cavernomas not visible on routine sequences. 1, 7
• Contrast enhancement may increase conspicuity but is not always necessary for diagnosis. 1
• Cavernomas are typically angiographically occult on catheter angiography due to sluggish blood flow, distinguishing them from high-flow vascular malformations. 1
• Non-contrast CT may show acute hemorrhage but is less sensitive than MRI for detecting non-hemorrhagic cavernomas. 1

Common Pitfalls

• Do not confuse cavernomas with infantile hemangiomas—the terms "cavernous hemangioma" and "cavernous angioma" are outdated misnomers that incorrectly suggest a proliferative neoplasm rather than a congenital malformation. 1
• Venous malformations and deep developmental venous anomalies have historically been misdiagnosed as "cavernous hemangiomas." 1
• Cavernomas do not exhibit the proliferative characteristics of true vascular tumors and should be classified as vascular malformations, not neoplasms. 1