Small cell carcinoma of the major salivary glands.

Small cell carcinoma is primarily a pulmonary neoplasm that rarely arises in extrapulmonic sites including salivary glands of the head and neck. Twelve cases of small cell carcinoma of salivary gland origin were retrieved from the Armed Forces Institute of Pathology files. Six tumors occurred in the parotid gland and six in the submandibular gland. Tumors were classified into two categories: those with areas of histologically typical small cell carcinoma (7 cases) and those with areas of typical small cell carcinoma with foci of ductal differentiation (5 cases). Follow-up information was available in all 12 cases. Electron microscopy was done on eight tumors; only one demonstrated round electron dense intracytoplasmic neurosecretory granules. These observations further support evidence in the literature suggesting most of the small cell carcinomas of salivary gland origin are not true neuroendocrine ("oat cell") carcinomas, but actually are small cell ductal carcinomas. These tumors appear to have a better prognosis than small cell carcinoma of the lung or nonsalivary gland sites in the head and neck region, with an estimated 2- and 5-year survival of 70 and 46%, respectively.