Abstract
A 5-year-old African American male was referred to dermatology clinic for evaluation of a tender nodule on his left arm thought to be a cyst versus a keloid. The lesion had been present for approximately three years with significant accelerated growth over the previous six months. Physical examination revealed an indurated nodule 3.2 cm x 2.8 cm on his lateral anterior left arm. A 4 mm punch biopsy was performed and histology demonstrated an atypical spindle cell proliferation. Immunohistochemical stains for CD34 showed patchy positivity within the tumor and MIB-1 showed an elevated proliferation index within the tumor cells. The tumor cells were negative for factor XIIIa, SOX10, SMA, Desmin, and S-100. pigmented (Bednars tumor) dermatofibrosarcoma protuberans with fibrosarcomatous transformation. DFSP is as a rare, locally aggressive cutaneous tumor with slow infiltrative growth.The fibrosarcomatous FS-DFSP has a higher metastatic potential than ordinary DFSP; however, both often locally recur after resection. The fibrosarcomatous variant, FS-DFSP, differs from classic DFSP in that there is higher cellular density with a herringbone or fascicular pattern, can show cytologic atypia and many mitoses. It also often has a lower CD34 expression compared to typical DFSPs. Pediatric patients with FS-DFSP have similar rates of local occurrence, with four of thirteen having local recurrence, while three out of thirteen cases had distant metastases leading to death in two of thirteen cases. Complete surgical resection with clear margins is necessary to prevent relapse.
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