Nerve sheath myxoma (neurothekeoma) of the gingiva, a case report and review of the literature

Abstract

Nerve sheath myxoma (NSM) is a benign peripheral nerve sheath tumor that rarely occurs in the oral cavity. Among the 23 reported intraoral cases, no lesion has previously been reported on the gingiva. In this report, we describe the first gingival case of oral neurothekeoma with histopathologic and immunohistochemical characteristics. The patient, a 32 year old female presented with a slowly growing gingival mass diagnosed clinically as an epulis. The lesion was surgically excised. Histopathologically, the lesion presented as a submucosal multinodular mass composed of spindle and stellate-shaped cells with a myxoid background. Immunohistochemically, the tumor cells were sporadically positive for S-100 and NSE and negative for GFAP, EMA, SMA, CD68 and HMB45. The immunoprofile of this lesion confirmed a Schwann cell origin. The lesion was followed up for 10 months with no reports of recurrence.

Fig. 1

Hematoxylin and eosin stain of neurothekeoma section (10×). Notice the well demarcation of the lesion from superficial submucosa

Fig. 2

Hematoxylin and eosin stain of neurothekeoma sections (20×). Note the presence of thick, short collagen bundles and focal myxoid areas. Note the presence of epithelioid/stellate cells

Fig. 3

Immunohistochemical stain of S100 protein counterstained with hematoxylin, using horse radish peroxidase technique (40×). Note the positivity of thin spindled neural cells in short fascicles presented as brown/darkly stained cytoplasm. Note the presence of a mast cell in the rounded rectangle

Fig. 4

Immunohistochemical stain of NSE protein counterstained with hematoxylin, using horse radish peroxidase technique (40×). Note the positivity of some of spindled and stellate tumor cells presented as brown/darkly stained cytoplasm