Necrotizing sialometaplasia: a source of confusion with carcinoma of the palate.

Necrotizing sialometaplasia is a self-healing nonneoplastic disease of the hard and soft palate characterized by one or two deeply excavating ulcers. Histologically, there is necrosis of the mucous cells of the minor salivary gland tissue with partial replacement by squamous epithelium. The deeply situated squamous epithelium intermixed with mucous cells may lead to the erroneous diagnosis of squamous carcinoma or mucoepidermoid carcinoma. The confinement of cytologically benign squamous epithelium to the pre-existing lobular pattern of the salivary gland should permit an accurate histologic diagnosis by biopsy and avert further surgical intervention.