Solitary fibrous tumor of the hypoglossal nerve.

We report a case of solitary fibrous tumor (SFT) causing isolated hypoglossal nerve palsy. The neuroimaging appearance of the tumor was indistinguishable from that of schwannoma or meningioma. Immunohistochemical tests demonstrated strong reactivity for CD34 but an absence of staining for S100 and epithelial membrane antigen; this profile is indicative of an SFT. SFTs are mesenchymal tumors that can affect the dura-covered segments of cranial nerves. They may be considered in the differential diagnosis of an isolated cranial nerve palsy.