Cholesterol cyst manifesting as a middle ear vascular tumor.

A localized, cystic, "blue ear drum" (idiopathic hymotympanum) mimicking a middle ear vascular tumor occurred in a 12-year-old boy. This lesion must be included in the differential diagnosis of suspected vascular mass of the middle ear. A history of eustachian tube dysfunction should be sought. Physical examination is usually not diagnostic, and a full radiologic evaluation is essential in order to rule out a high jugular bulb, an ectopic carotid artery, or a glomus tumor.