Pigmented pleomorphic adenoma, a novel melanin-pigmented benign salivary gland tumor

Abstract

This paper reports a pleomorphic adenoma with grossly visible pigmentation resulting in the macroscopic appearance of melanotic lesion in a 33-year-old Japanese male. In addition to the characteristic histopathological features of a benign pleomorphic adenoma, variously formed and -sized cells, many of which were considered to be melanocytes, containing melanin pigment in their cytoplasm, were distributed in the epithelial component. In addition, melanin pigment was deposited in tumor cells of duct structures. Furthermore, condensed secretory substances with marked pigmentation were frequently seen in the tubular lumina. Perusal of the English language literature revealed only two cases of parenchymal pigmentation of salivary gland tumors: both were mucoepidermoid carcinoma. The possible histogenesis of melanocytes in the salivary gland lesions is discussed, though no firm conclusion could be drawn.

A case of mucoepidermoid carcinoma with melanin pigmentation manifested in the palate

“…Melanocytes are sometimes scattered in the periductal and periacinar regions around the duct system [6], and a case of benign salivary gland tumor with melanin pigmentation was recently reported [7]. In the present case, pigmented inclusions within dendritic melanocytes and melanin granules were detected histopathologically as well as histochemically; these were not present in the normal minor salivary gland but were found in the tumor and in the normal epithelium around the components of the MEC.…”

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

“…The authors have studied the occurrence and distribution of melanocytes in normal salivary glands and salivary gland tumors from Japanese patients, and have discussed their possible histogenesis and pathological significance (18)(19)(20)(21). The present paper reports a case of welldifferentiated mucoepidermoid carcinoma in which the parenchyma contained numerous melanocytes.…”

“…Only 5 tumors of salivary gland origin containing numerous melanocytes and melanin pigment in the parenchyma and/or stroma have been documented (15)(16)(17)(18)(19). Moreover, a review of the literature has yielded no convincing examples of pre-existing melanocytes in the salivary glands.…”

“…A review of the literature yielded only four documented cases of salivary gland tumor in which the parenchyma contained melanocytes: three cases of mucoepidermoid carcinoma (15)(16)(17), and one of pleomorphic adenoma (18).…”

Melanin bearing myoepithelial cells in a pigmented salivary gland carcinoma: a new avatar of myoepithelial cell? A case report

“…The other cases were of mucoepidermoid tumors, where the pigment-producing cells were proved to be melanocytes [1][2][3]8]. More recently, a case of pleomorphic adenoma with melanin pigment has been described [7].…”