Clear Cell Pleomorphic Dermal Sarcoma: A Case Report and Literature Review

Introduction: Atypical fibroxanthoma (AFX) and pleomorphic dermal sarcoma (PDS) are one spectrum of rare cutaneous neoplasms that typically arise in sun-exposed skin of older population. AFX/PDS is essentially diagnosis of exclusion requiring Immunohistochemical work-up to exclude other types of tumors. Case Report: We present a case involving an ulcerated solitary lesion on the scalp of an elderly man. Histological examination revealed that the dermal tumor was composed of large pleomorphic, epithelioid, and spindle cells with clear cytoplasm. These cells were negative for cytokeratins, melanocytes and smooth muscle markers, but positive for CD10. These findings are consistent with a diagnosis of clear cell (CC) PDS. Conclusion: PDS is a low-grade malignancy that can recur locally and metastasize, which is distinguished from AFX by its larger size and the presence of aggressive histopathologic features including deeper invasion into the subcutaneous tissue, tumor necrosis, and lymphovascular and/or perineural involvement. Among several histopathologic variants, the CC variant is extremely rare with only two cases of PDS reported in the literature to date.