Abstract

We present a case of primary dermal sarcomatous carcinoma that clinically mimicked metastatic squamous cell carcinoma (SCC). Our patient is an 83-year-old skin type 2 male with a recent history multiple cutaneous squamous cell carcinomas that presented for mohs re-excision of a biopsy proven SCC on his left forearm. The patient had previously undergone wide local excision that resulted in positive margins. After clearing the tumor, and while planning the repair, a 2-centimeter dermal nodule was noted proximal to the surgical defect. Given the potential for metastatic disease, a biopsy was obtained while the remainder of the surgical defect closed primarily. Histopathologic sections demonstrated a well circumscribed, unencapsulated, highly cellular dermal proliferation composed of markedly atypical cells with significant pleomorphism, prominent nucleoli and abundant, non-uniform, amphophilic cytoplasm. The cells of interest stained strongly and diffusely with vimentin, CD99, CD163, INI-1 and BRG-1, with a diffuse blush positivity with CD10 and CD68, focal positivity with AE1/3, CK HMW, CAIX and FLI-1 and no significant positivity with GLYPI-3, SOX10, Melan A, S100, CK5/6, p63, SMA, Desmin, NSE, CD45, PAX8, CK8/18, CD31, CD34, HMB-45, ERG and NKX3.1. Overall staining pattern was most suggestive of a primary cutaneous sarcomatous carcinoma.Primary cutaneous sarcomatous carcinomas are rarely reported in the literature, but are uniformly associated with a poor prognosis. Greater than one year following excision and adjuvant radiation, however, our patient has demonstrated no evidence of recurrence or metastasis to date.

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