Oral focal mucinosis: review of the literature and seven additional cases.

Oral focal mucinosis (OFM) is a rare, asymptomatic, benign lesion of unknown etiology that usually involves the mandibular gingiva. This article reports on seven patients, six of whom had lesions that involved the gingiva and one that involved the palate. All cases demonstrated the classic lobular, myxomatous mesenchymal tissue with stellate cells. In all cases, immunohistochemical staining for S-100-protein expression was negative, thus excluding the principal differential diagnoses of myxoid neurofibroma and neurothekeoma (nerve sheath myxoma). This article seeks to bring OFM to the attention of clinicians and pathologists who must consider the differential diagnosis of gingival and palatal nodules.