Atypical cutaneous fibrous histiocytoma (ACFH) is not well known and only a small number of cases have been reported. Characteristically, ACFH is found on the trunk and limbs of middle-aged women. Although considerable cellular atypia may be present, it occurs focally, the remainder of the tumor representing more classical cutaneous fibrous histiocytoma. A 37-year-old woman presented with a solitary brownish firm nodule on her right forearm. No other abnormalities were found in her personal or family history. Clinically, the tumor simulated a benign fibrous histiocytoma. Histologic examination revealed a poorly delineated intradermal tumor with the usual appearance of benign cutaneous fibrous histiocytoma, but a variable pro-portion of cells in the tumor were scattered atypical cells or bizarre multinucleated giant cells. We report upon a rare case of ACFH.