Epithelioid sarcoma in FNAB smears

FNAB smears of eleven epithelioid sarcomas were reviewed and analysed. Ten cases had a very similar cytomorphologic picture composed predominantly of dissociated epithelioid-like cells with eccentrically placed nuclei. These tumors were clearly malignant but difficult to differentiate morphologically from melanoma, epithelioid leiomiosarcoma, and Schwannoma or adenocarcinoma. One case was composed of spindle cells and was reminiscent of a fibrohistiocytic tumor. Immunocytochemical reactions to vimentin and cytokeratin were performed in six cases on the Papanicolaou stained smears. The reactions to both antigens were positive in all six cases. Ultrastructural characteristics of eight of the tumors are also described. It seems that epithelioid sarcoma has a rather distinct cytomorphologic picture. Taking into consideration clinical data and using also immunocytochemistry, a definitive diagnosis of epithelioid sarcoma can probably be given from FNAB smears.