Epidermoid cysts of the fourth ventricle: very long follow up in 9 cases and review of the literature.

This study reports late surgical results obtained in 9 patients operated on for an epidermoid cyst of the fourth ventricle. They represent 19/9% of all cases of epidermoids treated at our Department over a period of 25 years (1975-2000). 7 cases were diagnosed with CT and 2 cases with MR. Duration of clinical history ranged from 2 months to 6 years (mean: 2,2 years). Preoperatively, 2 cases presented spontaneous remission of neurological symptoms and signs lasting about 1 year. 7 (77,8%) patients underwent subtotal removal of the cyst whereas in 2 patients the lesion was totally excised. 3 patients (33,3%) underwent a second operation for symptomatic recurrence diagnosed between 10 and 17 years from the first operation. At present, 7 (77,8%) patients are alive (mean follow up of 14,5 years, ranging from 5 to 23 years) without neuroradiological and clinical evidence of tumour recurrence. In this group, 6 have no neurological problems and 1 suffers from a light vestibulo-cerebellar syndrome. Fourth ventricle epidermoids have a good long-term prognosis even in the case of only subtotal removal. Follow-up clinical and MR controls allow an earlier diagnosis of recurrence. Surgery of recurrent cysts can be more demanding; nonetheless, long term prognosis can be quite good for patients in well preserved neurological condition.