Hemorrhagic cavernoma or ruptured dermoid of the orbit: Diagnosis with MRI.

MRI is a useful tool to study space-occupying lesions of the orbit. We present two cases of intraorbital lesions that were found to be a hemorrhagic cavernous hemangioma and a ruptured dermoid, respectively. The difficulties in arriving at the diagnosis of these rare entities with MRI are discussed. In general, dermoids are characterized by a peripheral, extra-conal location in the immediate vicinity of an orbital suture, while cavernous hemangiomas tend to be intraconal. Secondary complications of both entities, such as hemorrhage or rupture, may alter the characteristic MRI signal patterns found in uncomplicated lesions. Inflammatory reactions may be observed. The signal of the fatty dermoid and the hemorrhagic part of a cavernoma are both of high intensity on the T1-weighted images, and this may lead to diagnostic difficulties.