Many faces of mixed medullary-follicular and papillary carcinoma of the thyroid

Merged histological types of malignant thyroid tumor: experience and controversy

Malignant tumors of the thyroid that consist of merged histological types are a rare clinical entity, with an obscure pathogenesis and no consensus of opinion on nomenclature. Eight patients with merged histological types of thyroid malignant tumor at a single medical center were enrolled between January 1977 and December 2009. These patients were surgically treated and were followed postoperatively from 1 month to 34 years. Preoperative patient characteristics, B-type ultrasonography, computed tomography scan, thyroid function tests, postoperative pathology, immunohistochemistry, and prognosis data were collected. Merged histological types of thyroid malignant tumor accounted for 0.12% of all thyroid malignant tumors treated during this period. Preoperative imageology and laboratory data have no specific value toward diagnosis of merged histological types of thyroid malignant tumor. Merged histological types of thyroid carcinoma that had undergone radical resection in combination with hormonal therapy and I(131) radiotherapy achieved a satisfactory outcome, while other merged thyroid malignant tumors were usually associated with a poor prognosis. Prognosis depended on the highest grade among an individual group of malignant tumors.

Follicular-patterned lesions of the thyroid: the bane of the pathologist

This review focuses on follicular-patterned lesions of the thyroid gland and their differential diagnosis. Included are a discussion of the features differentiating follicular adenoma from adenomatous or hyperplastic nodule and follicular adenoma from follicular carcinoma and the follicular variant of papillary thyroid carcinoma. The cytologic and histologic characteristics are described, and criteria for diagnosing the major follicular lesions are reviewed.