Intraoral nerve sheath myxoma: case report and systematic review of the literature.

BACKGROUND Oral nerve sheath myxoma (NSM) is an uncommon benign neoplasm with Schwann-cell origin, which is frequently mistaken for neurothekeoma. We report a case of NSM on the buccal mucosa in a 42-year-old woman. This case is compared with previously reported cases and a systematic review is performed. METHODS AND RESULTS We conducted a case report and systematic review of oral cases considered true NSMs. A literature search was performed using PubMed, Lilacs, Scielo, Cochrane, SciVerse Scopus, Web of Science, and Embase electronic database. Twenty-five cases of oral NSM were included in the systematic review. CONCLUSION Oral NSM is rare and may represent a diagnostic challenge for pathologists. To confirm the diagnosis of NSM, the evaluation of S-100 protein expression or other neural marker is essential. The use of the terms NSM and neurothekeoma as synonymous or as variants of the same tumor should be avoided, because they are clearly distinct lesions.