Solitary (unicameral) cysts involving the temporal bone.

The primary unicameral cyst which involves the temporal bone is very rare. Only about 30 patients have been reported in the literature during the past ten decades. The lesion is most frequently encountered in the first and second decade of life. In contrast to the other locations in the skeleton, it usually remains asymptomatic for a long time until it causes a deformity or dysfunction. The etiology has so far remained obscure. Its occasional association with malformations of the ears and nasopharynx and other developmental anomalies, its incidental bilateral occurrence, and certain histological aspects may suggest a congenital origin or a localized defect in bone formation and remodeling.