Dermatofibrosarcoma protuberans (DFSP) is an uncommon subcutaneous fibrous tumor which is classified as having "intermediate malignant potential". It shows infiltrative growth in subcutaneous tissue, recurrence, and rarely the ability to transform or metastasize.

Clinically, it commonly presents as an indurated plaque or cutaneous nodules. The most common locations of DFSP are the trunk and proximal extremities, but they can also be seen on the scalp, neck, face and distal extremities. They are seen most often in young to middle-aged adults.

Microscopically, these tumors have characteristic patterns of a dense proliferation of uniform, bland looking spindle shaped cells arranged in a storiform pattern and also appear in the deep dermis with characteristic "honeycomb-patterned" subcutaneous fat infiltration. It may also show subcutaneous fascia and muscle invasion.

The main differential diagnosis is Cellular fibrous histiocytoma/Cellular dermatofibroma (CDF). Immunohistochemistry shows CD34 is positive in DFSP, whereas Factor Xilia is positive in CDF.

The overall prognosis for DFSP is excellent, however as it shows high local recurrence, complete surgical excision of the lesion is crucial.

This slide shows CD34 stain. See Related Content for H&E stain.