Surgical Treatment of Right Atrial Metastasis of the Malignant Melanoma: A Case Report

Malignant melanoma has a high propensity for cardiac metastasis, with autopsy studies reporting an incidence of 47-64%. However, in living patients, Cardiac Metastases of Malignant Melanoma (CMMM) are rare (<2%) and often diagnosed postmortem. A 46-year-old woman was presented with dyspnea and fatigue. Sixteen years earlier, she had undergone treatment for malignant melanoma of the right forearm. Echocardiography revealed a right atrial mass (6.5×3.7 cm) intermittently obstructing the tricuspid valve and a smaller mass in the right atrial appendage. PET imaging showed no systemic metastases. Due to the risk of tricuspid obstruction and embolization, the patient underwent emergency surgical resection. Histopathology confirmed metastatic malignant melanoma. Postoperative recovery was uneventful, and she was discharged on postoperative day 11 to continue oncology-directed therapy. At six-month follow-up, she remained asymptomatic. CMMM can present decades after primary melanoma treatment. Advances in imaging facilitate earlier detection, yet diagnosis remains challenging. Surgical excision is the preferred treatment in symptomatic cases. Despite historically poor prognosis, survival has improved with modern immunotherapy. This case underscores the importance of lifelong melanoma surveillance and timely surgical intervention in cases of cardiac obstruction.