Monarch Disease Ontology entry MONDO_0006463 (thyroid gland mucoepidermoid carcinoma) is a primary, low grade carcinoma of the thyroid gland composed of groups of squamoid and mucous cells, surrounded by fibrous tissue. Prominent cystic structures may be present. The clinical course is usually indolent. Also known as: mucoepidermoid thyroid carcinoma, mucoepidermoid thyroid gland carcinoma.