Hemorrhage owing to cerebral cavernous malformation: imaging, clinical, and histopathological considerations

Cavernous malformation (CM) is the second most common cerebral vascular malformation and is often found incidentally. Their natural history is usually benign, however, patients with CM who present with symptomatic hemorrhage may later follow a serious clinical course if left untreated. The risk of hemorrhage is associated with previous hemorrhage, lesion location (infratentorial and deep), and the presence of associated developmental venous anomaly (DVA). Histopathological specimens also indicate that coexistence of DVA and other vascular malformations may be associated with hemorrhage owing to CMs. Diagnosing CMs is difficult, even in patients who initially present with symptomatic hemorrhage. Computed tomography scans typically reveal a hemorrhagic CM as a nonspecific heterogenous mass of high density, which may not be misdiagnosed as a solitary hematoma, especially when located in the infratentorial region. Magnetic resonance imaging demonstrates internal loculation with mixed-signal intensities typical for CMs, although this may be partially or completely masked by acute hemorrhage. Susceptibility-weighted imaging (SWI) reveals a significant "blooming" effect of hemosiderin deposition. Three-dimensional postcontrast T1-weighted imaging is essential to identify associated DVAs, and this is important for both diagnosis and planning of surgical treatment. Contrast-enhanced MRI should be performed to diagnose hemorrhagic CMs and differentiate them from spontaneous solitary hematoma or hemorrhagic tumors.