FNA diagnosis of dermatofibrosarcoma protuberans

Fine-needle aspiration (FNA) features of primary and recurrent dermatofibrosarcoma protuberans (DFSP) in two patients were evaluated and correlated to ancillary studies and clinical data. The tumors developed in the skin and subcutaneous tissue of the back in both patients. The cytological findings included clusters and dispersed uniform or slightly atypical spindle cells, collagenous matrix, and, in one case, cell clusters with a storiform pattern. Both tumors were diagnosed correctly when FNA was complemented by ancillary studies (immunostaining) and clinical data. FNA features alone are not sufficiently characteristic to permit a confident diagnosis of DFSP. Correct diagnosis requires an awareness of the clinical history and the use of ancillary studies.