BACKGROUND Masses in the right ventricle are uncommon, but if present, they are most often attributed to either primary cardiac tumors or metastatic disease. METHODS A 50-year-old woman presented with progressive lower extremity edema and was diagnosed with a right ventricular mass causing severe tricuspid insufficiency and near-total obstruction of the pulmonary artery. She had a history of hysterectomy for uterine leiomyomatosis. Based on imaging and histological findings, a diagnosis of benign metastasizing leiomyoma (BML) was made. The patient underwent successful resection of the mass, tricuspid valve replacement, and implantation of a right ventricle-pulmonary artery conduit. CONCLUSIONS Cardiac metastasis from BML is extremely rare, particularly in the right heart. Although histologically benign, BML can lead to life-threatening cardiac complications. This case emphasizes the importance of thorough cardiac assessment in patients with a history of leiomyoma and unexplained symptoms. Early diagnosis and surgical management are essential to prevent serious outcomes. CONCLUSIONS BML, though rare, can cause life-threatening cardiac involvement. Clinicians should consider a comprehensive cardiac evaluation for patients with unexplained cardiac symptoms and a history of leiomyoma.