Neurothekeoma of the Oral Cavity: Report of two cases of a distinctive variant and review of the literature.

Abstract

Oral Med Pathol 6(2001) 95 IntroductionNeurothekeoma (NT) including nerve sheath myxoma (NSM), is a rare neoplasm arising from the endoneurium of the peripheral nerves. In 1969, Harkin and Reed (1) were the first to report on this tumor in the dermis, and they termed it "myxoma of the nerve sheath". The tumor was characterized by a lobular proliferation of myxomatous tissue separated by fibrous septa. Subsequently, Gallager and Helwig (2) reported 53 cases of a benign tumor of the dermis and subcutaneous tissue that was histologically suggestive of "Schwann cell tumor", which they called NT. Since then, the differential diagnosis between NSM and NT has been controversial. Generally, the prevailing view has been that NSM and NT are predominantly myxoid and cellular variants of the same tumor (3), and Pulitzer and Reed (4) accepted these two lesions as synonymous in a broad sense. However, Laskin et al. (5) stated that NSM is only a hypocellular variant in the myxoid type of NT. In 1996, the World Health Organization "Histological Typing of Skin Tumours" (6) stated that NSM may represent a variant of NT with increased mucin deposition associated with greater age, and NT may be subdivided into cellular and myxoid variants. Recently, immunohistochemical analysis has been performed to determine the subdivision of NT, but there is no consistency of immunoreaction in some cases. Thus, the precise relationship between NSM and NT has not yet been completely established due to disagreement among investigators. NT often develops in the dermis and subcutis of the face, extremities, trunk and the shoulders (6), and very rarely in underlying mucous membranes. Previously, only 16 cases of intraoral NT have been reported (2,4,(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18). We describe the clinical and pathologic features of two cases of NT as a distinctive variant: a mixed variant arising in the buccal mucosa and a myxoid variant arising in the inferior surface of the tongue. In addition, previously reported intraoral lesions of this tumor are reviewed. Case Reports Case 1A 59-year-old man visited our outpatient clinic on May 20, 1992, with a chief complaint of a gradually enlarging mass in the buccal mucosa. The patient had repeated formation of a submucosal hematoma in the left buccal mucosa during the prvious two years, due to biting. Physical examination revealed a pedunculated polypous mass measuring 10¥14¥7 mm in size on the left buccal mucosa corresponding to the bite-surface of the Neurothekeoma of the Oral Cavity: Report of two cases of a distinctive variant and review of the literature

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

“…Nerve sheath myxoma (NSM) is an uncommon benign peripheral nerve sheath neoplasm first described in 1969 by Harkin and Reed and Scheithauer et al This neoplasm arises most commonly within the dermis and subcutaneous tissues on the face and upper extremities and is extremely rare in the intraoral region . Intraoral NSM was first reported in 1974 by Mincer and Spears and few cases in the oral mucosa were reported so far in the medical literature …”