MULTIPLE SCHWANNOMAS - SCHWANNOMATOSIS OR NEUROFIBROMATOSIS TYPE-2

Object. The aim of this study was to clarify the clinical outcome of s chwannomatosis, a rare condition characterized by multiple nonvestibul ar schwannomas in the absence of meningiomas, intraspinal ependymomas, and other clinical signs of neurofibromatosis type 2 (NF2). Methods. Nine patients with schwannomatosis heated at one institution are prese nted and their clinical course during a median follow-up time of 9.9 y ears is discussed. The patients were typically middle-aged at the time of their first operation (median 43.5 years), none had a positive fam ily history of schwannomatosis or NF2, and none showed cutaneous or oc ular signs of NF2. On histopathological examination the tumors from th e patients with schwannomatosis showed a lobular appearance and freque nt Verocay bodies, signs indicating NF2, more often than 20 sporadic s chwannomas that were investigated as controls. Two patients died of un related causes at 3.2 and 9.9 years, respectively, of follow up. Magne tic resonance images of the head and spine were obtained in seven pati ents at the end of the followup period. New spinal schwannomas were de tected in one patient and a residual schwannoma in three. No germline mutations of the NF2 gene were found in these seven patients. Two addi tional patients originally included in the schwannomatosis group who w ere 8.6 and 11.7 years old at initial surgery had NF2. One was diagnos ed at follow-up review and the other developed a fulminant disease tha t led to death in 4 years. Conclusions. The clinical course, long-term outcome, and genetic mechanism of schwannomatosis differ from that of NF2.