Giant pilomatrixoma: conventional and diffusion-weighted magnetic resonance imaging findings

ernous. A purely epidural hemangioma is a rare lesion, representing only 4% of epidural lesions, and the cavernous subtype is the most commonly found in this region. The lesion is located in the posterior region of the spine in up to 93% of cases and the dorsal spine is affected in 80% of cases. Epidural cavernous hemangioma is most commonly found in men (at a 2:1 ratio) aged over 40. Vertebral intraosseous involvement is frequent, with a prevalence of 11%. The clinical condition includes dorsal or lumbar pain, with signs of radiculopathy and myelopathy, and the patient is referred to undergo imaging study for suspicion of disk herniation. The clinical presentation is normally insidious, but acute clinical deterioration due to sudden increase in the lesion volume resulting from hemorrhage or venous occlusion. As the lesion is highly vascularized, the diagnostic suspicion is very important for the surgical planning, reducing the chances of bleeding during the procedure. Incomplete resection due to bleeding might lead to persistence of clinical symptoms and reoperation would be difficult because of local adhesions. Epidural hemangiomas are described as elongated and lobulated lesions, possibly with distinctive imaging findings depending on the subtype. Venous and arteriovenous hemangiomas present as cystic masses, generally with hypoor intermediate signal on T1-weighted and marked hypersignal on T2-weighted images with peripheral contrast enhancement. Capillary and cavernous hemangiomas are seen as solid masses, with hypoor intermediate signal on T1-weighted, marked hypersignal on T2weighted images, and intense contrast-enhancement. The main differential diagnoses of epidural hemangiomas include nerve sheath tumor, meningioma, lymphoma, abscess and extradural hematoma. Finally, cavernous hemangioma should be considered in the differential diagnosis of epidural lesion with hypersignal on T2weighted images and prominent contrast enhancement, particularly in case where the posterior region of the dorsal spine is affected.