ASSESSMENT AND SURGICAL-MANAGEMENT OF POSTERIOR-FOSSA EPIDERMOID TUMORS - REPORT OF 28 CASES

OBJECTIVE: The management of a series of 28 patients operated on for p osterior fossa epidermoids is reviewed, emphasizing the need for long- term follow-up. We discuss the rationale for a comprehensive classific ation system that may allow the comparison of results from homogeneous series. METHODS: We of grouped the tumors to differentiate the surgic al management according to various timer sites and the degree of exten sion. Twenty patients harbored tumors located in the cerebellopontine angle, five patients harbored tumors in the fourth ventricle, and thre e patients harbored tumors in the posterior fossa basal. In 17 patient s, extensions of turners outside the posterior fossa included the foll owing regions: the suprasellar/chiasmatic (n = 5), the parasellar/temp orobasal (n = 5), and the mesencephalic/pineal (n = 7). Tumor extensio n was also defined by tile number of regions involved, Pre-and postope rative magnetic resonance imaging and computed tomographic findings co llected in 17 and 28 patients, respectively, were carefully evaluated. RESULTS: Clinical features and surgical approaches varied according t o location and growth pattern, Fifty-seven percent of the tumors were completely removed. A higher total removal rate was achieved in patien ts with tumors confined to the primary location. One patient (3%) died in the perioperative period. Approximately half of the patients prese nted with transient mild focal deficit impairments resulting from the manipulation of the nervous structure over a wide area, There was a hi gher rate of surgical complications with fourth ventricle and mesencep halic extended cepebellopontine angle tumors, The mean follow-up perio d was 8.6 years. Thirty percent of the patients with subtotal removal experienced symptomatic recurrences after 8.1 years, whereas all patie nts with total removal were still asymptomatic. The recurrence-free su rvival rate was 95% at 13 years for patients with total removal compar ed with 65% for patients with subtotal removal, Problems of identifica tion of tumor regrowth are discussed, CONCLUSION: By assessing posteri or fossa epidermoids, we determined that location and extension play a major role in the prognosis, Our data suggest that more aggressive su rgery is called for at first operation, and that a second operation sh ould be planned when regrowth becomes symptomatic and/or tends to exte nd outside its original site.