Ancient neurilemmoma (schwannoma).

A clinical and light microscopic study of 11 patients with ancient neurilemmoma is presented. Ancient neurilemmoma is a cellular form of ordinary neurilemmoma, showing nuclear polymorphism and hyperchromasia. Seven patients were female and 4 were male; their ages ranged between 37 years and 81 years, with a median of 59 years. Seven tumours were 2.5 cm or larger in the widest diameter, and had been slowly enlarging for one year or more. All tumours were solitary, encapsulated showing nuclear polymorphism and hyperchromasia without any mitotic activity. The differential diagnosis is discussed. Follow-up information available on all patients confirmed that the clinical course is benign.