Mucinous carcinoma of the thyroid: A case report and review of the literature.

We report the case of a primary mucinous carcinoma of the thyroid in a man of 74 who had a 4-cm nodule in the right lobe of the thyroid, with a solido-cystic appearance on ultrasound associated with lymph node metastases. On scintigraphy, the nodule was hot and not extinctive. The patient underwent total thyroidectomy with a ipsilateral right lymph node dissection. The immunohistochemical study showed the negativity of CK 7 and CK 20 and the positivity of thyroglobulin and TTF 1. Postoperatively the rate of blood thyroglobulin 3 months after surgery had collapsed to 0.17ng/ml. The evolution was marked by the appearance of pulmonary metastasis and the patient died 4 months after surgery. Histological study showed the presence of almas of neoplastic cells surrounded by large deposits of extracellular mucin. Primitive mucinous carcinoma of the thyroid is a rare tumor which differential diagnosis is established on the positive immunohistochemistry of thyroglobulin and TTF1 but negative for other markers.