A rare presentation of a cutaneous metastasis from an undifferentiated pleomorphic sarcoma.

Undifferentiated pleomorphic sarcoma, a rare and aggressive soft tissue sarcoma, commonly affects the extremities and has a high propensity for local recurrence and metastasis. This case study presents a 57-year-old male with UPS in the right forearm, which progressed to rare cutaneous metastasis on the right chest wall following initial treatment. Despite undergoing wide local excision, flap reconstruction, and adjuvant radiation, the patient later developed disseminated metastases, including in the lungs, bones, liver, and skin. Immunohistochemistry confirmed metastatic pleomorphic sarcoma, leading to palliative chemotherapy. This case highlights the rarity of cutaneous metastasis in UPS, documented in less than 1% of cases, and underscores the diagnostic challenges posed by undifferentiated or poorly differentiated sarcomas. Timely diagnosis and multidisciplinary treatment are crucial in managing this aggressive malignancy, particularly when it presents with rare metastasis patterns. Further research is necessary to better understand UPS and improve therapeutic strategies.