Operative treatment of intracranial epidermoid cysts and cholesterol granulomas: report of 21 cases.

Thirteen patients had operations to remove intracranial epidermoid cysts, and long-term follow-up was obtained. Total or nearly total tumor and capsule removal was accomplished in 7 patients during the initial operation. This group required no additional operations. The other 6 underwent subtotal tumor removal and required multiple operations for symptomatic tumor recurrence. This latter group had a poorer neurological outcome. We conclude that initial total or near-total tumor resection is highly desirable in treating intracranial epidermoid cysts, particularly in physiologically young individuals. Five patients were followed after operations to remove pure cholesterol granulomas of the petroclival bone, and 3 additional patients were followed after operations to remove tumors with combined histopathological features of both an epidermoid cyst and cholesterol granuloma. Four patients with some component of a cholesterol granuloma had concurrent middle ear infections, and 4 did not. Intracranial subtotal excision and drainage of these lesions was the initial operative management in 7 patients, 5 of whom have required multiple operations for symptomatic tumor recurrence. Therefore, we conclude that subtotal excisional procedures for tumors with histopathological features of cholesterol granulomas are not usually successful in establishing long-term cures. Total excision, as recommended for epidermoid cysts, tumors frequently confused with cholesterol granulomas when occupying the petroclival region, may be warranted for these tumors as well. We postulate that when a congenital epidermoid cyst occurs in the petroclival bone, it may incite a local inflammatory reaction, producing lesions which have the histological features of both epidermoid cysts and cholesterol granulomas.