Atypical Histiocytoid Cells in Metastatic Papillary Thyroid Carcinoma

Fine-needle aspiration (FNA) of head and neck lymph nodes (LNs) is useful in diagnosing metastatic papillary thyroid carcinoma (PTC) and most commonly shows classic cytologic features of PTC. Metastatic PTC, however, may occasionally present with a pattern unfamiliar to most pathologists: atypical histiocytoid cells (AHCs). All PTC thyroidectomy specimens with associated FNA of LNs were retrieved from our files for 2007 to 2013. We aimed to...