Contributor: Gordon K. Klintworth
Mucoepidermoid carcinoma is malignant neoplasm characterized by the presence of mucus secreting cells and squamous epithelial cells. Mucin containing cysts of variable size are associated with solid epithelial nests. Some pathologists prefer not to define mucoepidermoid tumors in terms of adenoma or carcinoma. The mucoepidermoid carcinoma manifests a variable degree of malignancy, which is not always reflected in the histological appearance.
Mucoepidermoid carcinoma occurs most often in the salivary glands [carcinoma - salivary gland], but can also arise in other locations such as the bronchus [carcinoma - bronchus], trachea [carcinoma - trachea], breast [carcinoma - breast], and pancreas [carcinoma - pancreas]. It is a rare primary tumor of the thyroid gland [mucoepidermoid carcinoma - thyroid gland], conjunctiva [mucoepidermoid carcinoma - conjunctiva], and lacrimal gland [mucoepidermoid carcinoma - lacrimal gland]. Mucoepidermoid carcinoma of the conjunctiva and lacrimal gland have no systemic manifestations, and blood borne metastatses are rare. One variant of the mucoepidermoid carcinoma has a clear cell [mucoepidermoid carcinoma - clear cell].