Rare Late Cardiac Involvement Following Resected Primary Limb Dedifferentiated Liposarcoma: A Case Report.

Dedifferentiated liposarcoma (DDLPS) is a rare and aggressive subtype of soft tissue sarcoma, most commonly arising in the extremities or retroperitoneum. Cardiac involvement, whether primary or metastatic, is exceedingly rare and presents significant diagnostic and therapeutic challenges. We present the case of a 68-year-old woman with a history of lower limb DDLPS who experienced progressive dyspnea and was subsequently found to have a large mediastinal mass with pericardial involvement. Cardiovascular magnetic resonance (CMR) revealed imaging features consistent with a malignant lesion, including heterogeneous enhancement and tissue characteristics indicative of sarcoma. Given the patient's oncological history and the imaging findings, a diagnosis of metastatic cardiac DDLPS was favored. Surgical resection was deemed infeasible due to extensive pericardial involvement, and the patient underwent multiple lines of chemotherapy. Although there was initial disease control, she ultimately succumbed to septic shock resulting from a urinary tract infection. This case emphasizes the importance of considering metastatic sarcoma in the differential diagnosis of cardiac masses, particularly in patients with a known history of soft tissue malignancy. It also highlights the diagnostic value of CMR and the necessity for multidisciplinary management in complex, nonresectable cases.