Metastatic right atrial mass in the presence of atrial septal defect: A rare clinical coincidence.

Key Clinical Message: The key takeaway from this clinical scenario is to choose the most appropriate and reasonable treatment plan when dealing with a patient who has atrial septal defect (ASD) and concurrent atrial and mediastinal masses. In such cases, a heart-oncology team should make the therapeutic decision. Abstract: Right atrial masses are not pretty rare and might be a diagnostic challenge. Thrombosis, tumors, and vegetations are primary differential diagnoses. Workup for these masses usually includes multimodality imaging and biopsy in selected cases. We report a case of a 37-year-old lady who presented with cough, dyspnea, and head and neck swelling after a cesarean section. Echocardiography revealed a right atrial mass accompanied by a secundum type atrial septal defect (ASD). Pulmonary CT Angiography was performed, in which a lobulated mass in the anterior mediastinum was detected, and a heart-oncology team made the therapeutic decision. The patient was scheduled for surgical ASD closure and concomitant tissue biopsy. The pathology results were in favor of poorly differentiated germ cell tumors, and chemotherapy was started following the surgery. After two sessions of chemotherapy, the tumor did not respond to the primary regimen. Thus, an updated regimen was initiated. Compliance with the updated regimen was acceptable, and the patient is currently under treatment and follow-up.