Schwannomatosis: a clinical and pathologic study.

Schwannomas are benign nerve sheath tumors that most commonly occur singularly in otherwise normal individuals. Multiple schwannomas in a single patient are most often seen in neurofibromatosis 2 (NF2), but several recent reports suggest that schwannomatosis may also be a distinct clinical entity. We studied the clinical, radiographic, and pathologic features of 14 patients with multiple schwannomas who did not have vestibular schwannoma diagnostic of NF2. Most patients had peripheral nerve tumors that presented with pain. Many also had spinal nerve root and cranial nerve tumors. Three had multiple tumors limited to a single limb. We found that these 14 individuals did not exhibit phenotypic overlap with the neurofibromatoses. Only 1 of 14 patients had a positive family history. We conclude that patients with multiple schwannomas, who do not have vestibular schwannoma, comprise a distinct clinical problem, but further molecular genetic analysis is needed to define the pathophysiology of this disorder.