Abstract:

Atrophic dermatofibrosarcoma protuberans (DFSP) is an unusual variant of DFSP that can be misdiagnosed clinically and pathologically. We present a case of a 59-year-old woman who was incidentally found to have a 1.3 cm brown depressed plaque on her lower back that was concerning for atrophoderma or morphea. Biopsy of this lesion demonstrated a superficial dermal spindle cell proliferation arranged in parallel fascicles. S100 and CD34 stains were performed; S100 was negative while CD34 highlighted the lesional population. A differential diagnosis of plaque-like CD34-positive dermal fibroma versus atrophic DFSP was considered. Thus, a fluorescence in situ hybridization test for COL1A1-PDGFB mutation was performed and was positive, confirming the diagnosis of atrophic DFSP. The lesion was treated with Mohs micrographic surgery. There are a variety of clinical and histologic pitfalls with this entity, which was first reported in 1985 as dermatofibrosarcoma non-protuberans. Atrophic DFSP is not typically considered in the clinicians differential diagnosis based on appearance. Moreover, the atrophic variant of DFSP often lacks the typical storiform architecture seen in classic DFSP and may lead to misdiagnosis as a neurofibroma. S100 staining is useful in these cases to differentiate the two. Our case demonstrates the typical workup performed to avoid misdiagnosing this rare subtype of DFSP.

Financial Disclosure:
No current or relevant financial relationships exist.

Menu

Basil Patel, MD