Plexiform schwannoma.

We report the clinical, histopathologic, and immunohistopathologic features of two cases of plexiform schwannoma. This rare benign tumor is worthy of recognition because it can be misdiagnosed as plexiform neurofibroma. Differentiation from plexiform neurofibroma is important because the latter is pathognomonic of von Recklinghausen disease and carries a significant risk of malignant transformation. Plexiform schwannoma is, in contrast, not necessarily associated with von Recklinghausen disease and malignant transformation has never been observed.