A case of cardiac undifferentiated pleomorphic sarcoma treated with post-operative radiotherapy followed by heart transplantation

Cardiac undifferentiated pleomorphic sarcomas (UPS) are extremely rare tumors that typically arise in the left atrium. They behave highly aggressively, requiring multimodality treatment when complete surgical resection is not feasible. Nevertheless, there is ongoing debate regarding the efficacy of adjuvant radiation therapy and the associated risk of radiation-induced cardiotoxicity. Pathologically, there is an emerging connection between cardiac UPS and intimal sarcoma of the great vessels, supported by morphological and genetic similarities. Here, we present the case of a 63-year-old woman diagnosed with a large right ventricular UPS. The patient underwent incomplete tumor resection, which was followed by post-operative radiotherapy. After nine months, her cardiac function deteriorated rapidly, and she ultimately ended up requiring heart transplantation. We discuss this case in the context of the existing literature on the diagnosis and treatment of cardiac UPS, focusing on the histopathologic features of the heart after radiotherapy.