Hemophilic pseudotumor of the temporal bone with conductive hearing loss--case report.

A 46-year-old man with factor VIII deficiency presented with a rare case of hemophilic pseudotumor in the temporal bone manifesting as severe conductive hearing loss and external ear bleeding. The pseudotumor expanded and destroyed the temporal bone and skin of the external ear over the course of 8 years. The pseudotumor was surgically excised, and the patient's symptoms improved. Histological examination of a specimen collected from inside the pseudotumor demonstrated blood products in various stages of evolution and showed that the outer membrane consisted of a collagen layer. Hemophilic pseudotumors are rare complications occurring in 1-2% of patients with mild or severe hemophilia. Pseudotumors are chronic, slowly expanding, encapsulated cystic masses, and most are located in the long bones and pelvis. The present case suggests that cranial pseudotumor should be considered in the differential diagnosis of cranial lesion in a patient with hemophilia.