Ossifying fibromyxoid tumor misdiagnosed as follicular neoplasia. A case report

Fine needle aspiration of an ossifying fibromyxoid tumor (OFMT) at a prethyroidal location is initially misinterpreted as follicular neoplasia. Though the histopathologic criteria have been analyzed in detail, no experience with the cytologic features of OFMT is reported in the literature.

A 50-year-old male presented clinically with a recurrent goiter. Aspiration cytology (Giemsa stained) was characterized by a predominant fine fibrillary, pink matrix and moderate cellularity. The nuclei were eccentrically located, round to oval and slightly plemorphic, with fine chromatin. Focally, mild nuclear crowding and a few rosettelike structures were present.

The cytologic features were consistent with a soft tissue tumor of probably neurogenic origin, like OFMT. Differential diagnosis in this particular location not only included follicular thyroid neoplasms but also neurofibroma, neuroma, chondroma and, less likely, neuroepithelial tumors. However, since some diagnostic criteria of OFMT, like the nodular growth pattern and mature bone, can be found only histologically, the diagnostic value of aspiration cytology seems to be limited.