Aspiration cytology features of the warthin tumor-like variant of papillary thyroid carcinoma. A report of two cases.

BACKGROUND Warthinklike tumor of thyroid is a recently described variant of papillary thyroid carcinoma characterized histologically by a papillary architecture, oxyphilic tumor cells and extensive, chronic inflammation. CASES Fine needle aspiration was performed on solitary thyroid nodules in two females aged 19 and 35 years. Both patients complained of neck lumps, and the older one noted several months of fatigue and weight gain. The specimens were cytologically similar and were characterized by two distinct sets of features, one suggesting the tall cell or oxyphilic variant of papillary thyroid carcinoma and the other suggesting chronic lymphocytic (Hashimoto's) thyroiditis. Neoplastic follicular cell nuclei were divided into those with grooves, pseudoinclusions and hyperlobation consistent with papillary thyroid carcinoma, while other tumor nuclei exhibited a uniform, round contour; hypergranular chromatin; and relatively prominent nucleoli reminiscent of Hürthle cells. Chronic inflammation was abundant and intimately associated with neoplastic cell groups. CONCLUSION Warthinlike tumor of the thyroid possesses cytoplasmic and nuclear features with overlap with several other thyroid lesions. Although a definitive diagnosis at aspiration biopsy may be very difficult, the lesions are recognizably neoplastic and identifiable as probable or definite papillary thyroid carcinoma.