Fine-needle aspiration biopsy: dermatofibrosarcoma protuberans.

Dermatofibrosarcoma protuberans (DFSP) represents a spectrum of mesenchymal spindle cell tumors that typically involve both dermis and subcutis. Presented herein are six cases of DFSP, four of which were initially diagnosed by FNAB. The cytologic features useful in the identification of this lesion on Papanicolaou- and Diff-Quik-stained smears are discussed. Chief among these are the storiform stromal fragments, presence of entrapped adipose tissue and the recognition of fibrohistiocytic spindle cells. The potential pitfalls and the differential diagnostic possibilities of spindle-cell lesions, particularly those of fibrohistiocytic origin are discussed.