[Magnetic resonance imaging of the intraventricular cavernomas: diagnostic aspects]. / Ressonância magnética dos cavernomas intraventriculares: aspectos diagnósticos.

Cavernomas are vascular malformations that typically affect the white matter of cerebral hemispheres and brain stem. They are angiographically occult lesions that depend on magnetic resonance imaging (MRI) for their diagnosis, presenting a hypointense perilesional ring caused by hemossiderin deposition as seen in T2 sequences. The ventricular location is rare, and image features may differ. We present two cases with diagnosis made only by histopathologic examination, due to a lack of classic image findings. Cavernous hemangiomas must be included in the differential diagnosis of intraventricular tumors, and total surgical resection is the treatment of choice. Perilesional ring as demonstrated by MRI, must not be expected when dealing with such lesions.