Cellular neurothekeoma of the oral mucosa

Cellular neurothekeoma is an unusual benign neoplasm which, despite its nam e, is of uncertain origin. This report describes a cellular neurothekeoma o f the cheek mucosa, the first at this site. The tumour presented in I 29-ye ar-old man as I discrete mucosal thickening. Histology showed a generally w ell circumscribed, but unencapsulated, solid tumour which replaced the enti re lamina propria and permeated between minor salivary glands and bundles o f striated muscle in the submucosa. There was I sub-epithelial Grenz zone. The tumour was composed of nodules of pale, epithelioid cells separated by fascicles of spindle cells, with smaller strands and nests superficially. T he nuclei were vesicular and, though mainly bland, occasionally atypical. T he stroma was moderately infiltrated by mixed chronic inflammatory cells. P rominent nerves and blood vessels were seen at the periphery of the lesion, and neoplastic cells were noted within intact striated muscle fascicles. W ith immunohistochemistry, all the neoplastic cells strongly expressed NKI/C 3, synaptophysin, neurone-specific enolase and vimentin, some expressed smo oth muscle actin and PGP 9.5, but all were negative for S100, factor XIIIa, CD34, CD56, CD57, CD68, chromogranin A, desmin, epithelial membrane antige n and von Willebrand factor. The origin of the lesion is thus speculative. It was, however, completely excised Ind in 12 months there has been no recu rrence. (C) 2001 Elsevier Science Ltd. All rights reserved.