Warthin-like papillary carcinoma of the thyroid: A case report

Abstract

Objective: Warthin-like variant of papillary carcinoma (WLPCT) is an uncommon variant, first described in 1995, with a clinical presentation and prognosis similar to the classic papillary thyroid carcinoma (PTC). We report a case of WLPCT focusing on the histopathological and immunohistochemical features. Material and Methods: A 60-year old female, with no remarkable past medical history, underwent surgical treatment of an enlarged multinodal goiter with previous negative fine-needle aspiration biopsy findings. A left total and right subtotal thyroidectomy was performed. The patient is alive and well 4 months after the surgery. Results: On gross examination, the right lobe of the thyroid gland measured 4.5x1.5x1 cm, and the left lobe with adjoined isthmic lobe measured 5x3.5x2 cm. In the right lobe an oval, firm, grey, 0.8 cm large nodule was found, while in the left lobe another well-circumscribed, pale-brown, 2.5 cm large nodule was present. The left lobe nodule was diagnosed as an atypical follicular adenoma with no capsular or vascular invasion. Histology of the right lobe nodule showed an encapsulated tumor composed of papillary structures lined by oncocytic cells and rich lymphoid stroma, with germinal centers in the papillary stalks, typical for WLPCT. Immunohistochemically, tumor cells of WLPCT showed positive expression for cytokeratin 19, thyroid transcription factor-1 and thyroglobulin. Conclusions: Warthin-like variant is one of the rarest variants of PTC (less than 100 reported cases in the literature) with as favorable prognosis as the classic PTC. Morphology and immunohistochemistry are of decisive significance in differentiating these neoplasms from benign lymphoepithelial lesions, Hurthle cell carcinoma and tall cell variant of PTC.