A Case of Pleomorphic Dermal Sarcoma of the Forearm Treated with Surgical Excision and Postoperative Radiation Therapy = A Case of Pleomorphic Dermal Sarcoma of the Forearm Treated with Surgical Excision and Postoperative Radiation Therapy

다국어 초록 (Multilingual Abstract)

Pleomorphic dermal sarcoma (PDS), previously known as malignant fibrous histiocytoma, has been reclassified as undifferentiated pleomorphic sarcoma due to advancements in histological techniques, particularly in the case of skin-originating tumors known as PDS. Differential diagnosis, crucial for its aggressive nature, relies on clinical, histological, and immunohistochemical (IHC) analyses. We report a case of a 74-year-old male with a 5-cm exophytic lesion on the left dorsal forearm, diagnosed with PDS via punch biopsy revealing spindle and pleomorphic tumor cells in a storiform pattern. IHC staining exhibited positive CD10 and CD68 expression, while CD34 and desmin was negative. Subsequent imaging revealed significant muscle involvement, leading to a planned wide excision and postoperative radiation therapy. Herein, we report a rare case of PDS that occurred in an unusual extremity, discussing it with clinical and histopathological characteristics, along with a review of the historical nomenclature changes. (Korean J Dermatol 2025;63(1):5∼10)