A case of thyroid oxyphilic cell follicular carcinoma followed-up by fine needle aspiration cytology

Abstract

We report a case of thyroid oxyphilic cell follicular carcinoma (oncocytic carcinoma) in a 33-year-old Japanese man. The thyroid tumor measuring 20 mm in diameter was examined by fine-needle aspiration (FNA) cytology, and a diagnosis of benign oncocytic tumor was made. Five years later, at the time of surgery, the tumor had grown to 40 mm in diameter.

FNA cytology at the time of surgery showed oncocytes, in greater numbers and heterogeneity than in the previous examination. Histological examination of the resected tumor revealed the diagnosis of oncocytic carcinoma.

The cytological findings showed temporal histopathological changes of oncocytic carcinoma, including decreased follicular structures and increased cellular atypia.