Warthin-like Papillary Carcinoma of the Thyroid

Background.—Warthin-like papillary carcinoma of thyroid is characterized by distinct papillary formations lined by tumor cells with oncocytic cytoplasm, nuclear features of papillary carcinoma, and brisk lymphoplasmacytic infiltrates in the papillary stalks. This tumor derives its name from its close resemblance to Warthin tumor of major salivary glands. Design.—The clinicopathologic features of 17 patients with Warthin-like papillary carcinoma were studied. Results.—Fifteen tumors occurred in women and 2 arose in men (age range, 23–63 years). The lesions ranged in size from 3 mm to 2.5 cm. Fine-needle aspiration biopsies were performed in 7 cases; 4 were diagnosed as papillary carcinoma, 2 as consistent with lymphocytic thyroiditis, and 1 as atypical cells. All 17 tumors were confined to the thyroid; 6 showed prominent cyst formation and the remaining tumors were solid. In each case, the tumor arose in a background of lymphocytic thyroiditis. Nodal metastases were identified in 3 cases; however, none showed distant metastases. In 7 cases, foci of papillary microcarcinoma and follicular variant of papillary carcinoma were found in other areas of the thyroid. Conclusions.—Warthin-like tumors can be mistaken for benign lymphoepithelial lesions of the thyroid, Hürthle cell carcinoma, and tall cell variant of papillary carcinoma in both fine-needle aspiration and histology specimens. Follow-up information on the previously reported cases has suggested that these tumors behave similarly to usual papillary carcinoma. The extensive lymphocytic infiltration in these tumors and their association with chronic lymphocytic thyroiditis may suggest a role for immunological mechanisms in the pathogenesis of thyroid tumors.