Dermatofibrosarcoma protuberans : Reports of 5 cases.

We report the clinico-pathological features of 5 cases of dermatofibrosarcoma protuberance (DFSP) . The tumor size ranged from 2.2 to 10 cm. Four out of 5 tumors were surgically excised with the appropriate surgical margin of 4 cm and beyond the depth of fascia. No recurrence was seen in all cases under the follow up period of 6months to 8 years. The histological examinations revealed typical spindle-shaped nuclei with few mitoses, arranged in a storiform pattern, although one case contained foam cells and multinucleated giant cells within the tumor. Immunoperoxydase staining with anti-CD34 and anti-factor XIIIa antibodies showed that CD34 was positive in most of tumor cells and factor XIIIa was completely negative in 3 cases, while there was focal reactivity with both CD34 and factor X IIIa. The results suggest CD34 and factor XIIIa may be helpful to differentiate DFSP from other fibrohistiocytic tumors, these markers lack absolute specificity for this purpose.