Sclerosing Mucoepidermoid Cancer: A Unique Entity

Sclerosing mucoepidermoid thyroid cancer (SMECE) is a rare entity with less than 100 cases reported in the literature. Previously considered to have an indolent course, however, recent evidence has reported an aggressive nature ranging from local invasion to distant metastasis. We present a 66-year-old Caucasian female with SMECE who initially presented neck compressive symptoms. A thyroid ultrasound (US) revealed a solid hypoechoic mass replacing the left thyroid lobe. Fine needle aspiration cytology (FNAC) of the nodule resulted in suspicion of Papillary Thyroid Cancer, Bethesda category 5. The patient underwent total thyroidectomy and surgical pathology showed SMECE. Post-therapy whole-body scan following treatment with 150 mCi I-131 showed no residual or metastatic disease. SMECE is more common in females, between the third to eighth decade of life. Preoperative diagnosis may not be accurate given variable cytopathologic features. Differential diagnoses include primary squamous cell carcinoma of the thyroid, squamous differentiation of other thyroid malignancies, anaplastic thyroid cancer and nodular sclerosing variety of Hodgkin’s lymphoma. Due to its rarity, treatment of SMECE has ranged from thyroid surgery without or with radioactive iodine therapy, to surgery and external beam radiation and even chemotherapy.