Thyroid Gland Sclerosing Mucoepidermoid Carcinoma with Eosinophilia

**Semantic type:** Neoplastic Process

**Definition:** A rare type of mucoepidermoid carcinoma of the thyroid gland, usually associated with chronic lymphocytic thyroiditis. It exhibits a unique morphologic appearance consisting of a squamoid, nested growth pattern, dense fibrosis, and mucinous differentiation. The histogenesis of this unusual carcinoma has been debated, and it is unclear if it arises from remnants of the ultimobranchial body or from the follicular epithelial cells.

**Synonyms:** - SMECE - Sclerosing Mucoepidermoid Thyroid Carcinoma with Eosinophilia - Sclerosing Mucoepidermoid Thyroid Gland Carcinoma with Eosinophilia