Pigmented mucoepidermoid carcinoma, a case report and review of the literature on melanin-pigmented salivary gland tumors.

This paper reports a well-differentiated mucoepidermoid carcinoma containing numerous melanocytes in the parenchyma in a middle-aged Japanese man. In addition to the characteristic histopathologic features of well-differentiated mucoepidermoid carcinoma, various-formed and -sized, pigmented cells were widely distributed in the parenchyma. Many of these were considered to be melanocytes containing melanin in their cytoplasm. Perusal of the English-language literature revealed only four cases of salivary gland tumors with parenchymal pigmentation: three mucoepidermoid carcinomas and one pleomorphic adenoma. The possible histogenesis of melanocytes in the salivary gland lesions is discussed, although no firm conclusion could be drawn.