Sclerosing mucoepidermoid carcinoma of the submandibular gland: Report of two rare cases

Although mucoepidermoid carcinoma is the most common primary malignancy of the salivary glands, the sclerosing morphologic variant of this tumor is extremely rare, with only 15 reported cases. As its name suggests, sclerosing mucoepidermoid carcinoma is characterized by an intense central sclerosis that occupies the entirety of an otherwise typical tumor, frequently with an inflammatory infiltrate of plasma cells, eosinophils, and/or lymphocytes at its peripheral regions. The sclerosis associated with these tumors may obscure their typical morphologic features and result in diagnostic difficulties. Two cases of mucoepidermoid carcinoma of the submandibular gland associated with extensive central sclerosis and peripheral lymphoid response are reported. This unusual but distinctive variant of mucoepidermoid carcinoma can be difficult to recognize and may be confused with chronic sialoadenitis or even metastasis to an intra-parotid lymph node.