Isolated, Nonsyndromic Mucocutaneous Plexiform Neurofibromas: A Systematic Review of the Clinicopathologic Features.

Plexiform neurofibromas are benign neural tumors observed in association with neurofibromatosis. Isolated lesions exist. We conducted a systematic review of the published literature indexed in the PubMed/Medline database using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Thirty-five studies describing isolated plexiform neurofibromas were included detailing 41 tumors. Isolated lesions occur in all age groups, in both sexes and in all races. Cutaneous and mucosal lesions were reported. Asymptomatic, slowly enlarging masses were the most common clinical presentation, but lesions could be painful. Trauma-associated lesions were uncommon, but reported. Histopathologic features were similar to syndromic counterparts, but well-circumscribed/encapsulated lesions, rare association with diffuse neurofibroma, lack of reported malignant degeneration, and rare named-nerve origin were observed. Excision was curative in many cases, but recurrence could occur. Plexiform neurofibromas occur without neurofibromatosis in a subset of patients with isolated tumors.