Primary epidermoid cysts of the mastoid: clinical and treatment implications.

Epidermoid cysts of the temporal bone are extremely rare and such lesions arising in isolation within the mastoid bone have never been reported in literature. We report and describe the first two unique cases of primary epidermoid cysts arising in the mastoid bone. Of the two cases, one presented with progressive headache and imbalance and the other with unilateral hearing loss and tinnitus. Both cases needed CT and MRI scans and needed surgical management. We review the clinical presentations, histology, pathogenesis, radiological findings and management of these challenging cases. The diagnosis of an epidermoid cyst is based on clinical presentation, physical examination and especially the radiological, histological and intraoperative findings. Total removal of the lesion along with its capsule is recommended to prevent recurrence and to allow for a good long-term prognosis.