A Case of Atrophic Dermatofibrosarcoma Protuberans: DISCUSSION

25 Jan
2011

DFSP is an uncommon mesenchymal neoplasm originating in the dermis. About 1,000 cases have been reported since DFSP was first described. It usually occurs as an indurated plaque that slowly increases in size and develops multiple firm nodules. Rarely, the initial plaque may be atrophic or depressed, and this atrophic appearance may persist. Lambert et al first described 5 cases that resembled morphea or morpheaform BCC but showed typical DFSP on biopsy. They suggested that the term protuberans should be discarded from the name dermatofibrosarcoma protuberans. Atrophic DFSP is an uncommon clinical variant of DFSP. To our knowledge, there have been 31 reported cases of atrophic DFSP to date . While atrophic DFSP has a distinct clinical appearance, its epidemiology, histology and clinical behavior appear to be similar to the common protuberant type. Truncal involvement is seen in 79% of cases, and there is a slight female predominance (62%), with the average age of onset being 30 years. It presents as a large, irregularly outlined, tan to brownish depressed scar-like lesion with atrophic patch. It is generally asymptomatic, slow growing, and often benign appearance, thus diagnosis is frequently delayed (median delay 6 years) . It may be clinically confused with other atrophic or sclerotic dermato- logic conditions, such as morphea, anetoderma, morpheaform basal cell carcinoma, scar, and lym- phocytoma.

Histopathologically, atrophic DFSP is charac­terized by a dense spindle cell proliferation arranged in a cartwheel appearance infiltrating the surround­ing dermis and subcutaneous tissue. The tumor shows a deep / irregular infiltration of fatty tissue in a lacelike / honeycomb and multilayered pattern. Tumor cells are uniform spindle cells with little cytoplasm and elongated hyperchromatic, but not pleomorphic, nuclei. Usually there is little mitotic activity. The epidermis is normal or flat. The thickness of the dermis is reduced to < 50% of surrounding dermis, placing the subcutis close to the epidermis. The use of immunohistochemistry is a helpful adjunct to identify the tumor. The atrophic DFSP are consistently CD34 positive, factor XHIa and metallothionein-negative. viagra plus

Mohs’ micrographic surgery using immunohis- tochemical staining with CD34 on frozen section, is widely regarded as the treatment of choice for DFSP. Because lateral extensions of tumor cells into surrounding dermis are common, wide surgical excision might not be effective for these tumors. The rate of local recurrence is estimated at 70% with surgical margins of 1 cm, 40% with 2 cm, 15% with 3 cm, 5% with margins of 5 cm, compared with less than the 2% quoted in Mohs’ micrographic surgery. Recently, imatinib mesylate, which inhibits PDGF receptor tyrosine kinase, has been shown to have some effect on metastatic DFSP, and other compounds acting as platelet-derived growth factor receptor inhibitors are currently in clinical develop­ment such as SU11248 or SU9518.

The atypical appearance of atrophic DFSP may be misdiagnosed as other sclerotic and atrophic derma- tologic conditions including morphea and aneto­derma. Therefore it is important to recognize that DFSP begins and may persist as a non-protuberant plaque, often with an atrophic component. Greater clinical awareness of atrophic DFSP will allow earlier diagnosis and proper management. So we highlight this atrophic variant of DFSP.
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