Fine-needle aspiration of primary and recurrent dermatofibrosarcoma protuberans.

Dermatofibrosarcoma protuberans (DFSP) is a nodular cutaneous mesenchymal tumor of intermediate malignancy. Studies on fine-needle aspiration of DFSP are extremely rare; to our knowledge, only 33 cases have been reported. We have reviewed 14 examples of DFSP in 13 patients. Ten primary tumors were aspirated before surgical biopsy and four recurrent lesions (all from superficial lesions) were also investigated by fine-needle aspiration. All smears were surprisingly homogeneous and composed of isolated spindle cells in all cases (one unsatisfactory smear is excluded). Tissue fragments with a stroriform pattern were seen in 11 cases, fibrillary stromal fragments in 10 cases, naked nuclei in 8 cases, slight to moderate cytonuclear atypia in 5 cases. Mitotic figures, myxoid background, mast cells, and dispersed adipocytes were rare. Giant cells, necrosis, or marked cytonuclear atypia were not seen. DFSP shares morphological characteristics of some low-grade spindle-cell neoplasms. It should be differentiated from other benign low- and intermediate-grade spindle neoplasm such as low-grade fibrosarcoma, fibromyxosarcoma, low-grade malignant peripheral nerve sheath tumor, benign peripheral nerve sheath tumor, nodular fasciitis, and fibrous histiocytoma.