Tehran University of Medical Sciences Case Reports in Clinical Practice 2538-2683 8 5 2024 03 13 181 184 EN Akram Sardari Department of Cardiology, Imam Khomeini Hospital Complex, Tehran University of Medical Sciences, Tehran, Iran Mehrdad Salehi Department of Cardiovascular Surgery, Imam Khomeini Hospital Complex, Tehran University of Medical Sciences, Tehran, Iran Faeze Salahshour Department of Radiology, Imam Khomeini Hospital Complex, Tehran University of Medical Sciences, Tehran, Iran Ali Mehrakizadeh Department of Cardiology, Imam Khomeini Hospital Complex, Tehran University of Medical Sciences, Tehran, Iran Babak Sattartabar Trainee of Cardiology Residency, Department of Cardiology, Tehran Heart Center Hospital, Tehran University of Medical Sciences, Tehran, Iran 2022 12 20 2023 10 24 Cardiac involvement can occur in lymphoma, with the right heart being predominantly affected. The prognosis for patients with cardiac involvement is poor. A 28-year-old man, with a 4-year history of Hodgkin’s lymphoma, presented with progressive shortness of breath and ascites. Chest X-ray (CXR) and CT scan revealed multiple masses in the mediastinum. To exclude a pulmonary embolism, the patient underwent CT angiography, which incidentally revealed a filling defect in the right atrium. Trans-esophageal echocardiography confirmed the presence of a mass in the right atrium. Surgery was performed to obtain samples of the mediastinal masses and the right atrium mass. Pathological results indicated that the nature of the right atrium mass was diffuse large B-cell lymphoma (DLBCL), suggesting that the Hodgkin’s lymphoma had transformed into DLBCL. The transformation of Hodgkin’s lymphoma to DLBCL can occur, and cardiac involvement is not common. Given that the transformation of Hodgkin’s lymphoma into DLBCL can occur many years after the initial diagnosis, the authors recommend follow- up of these patients, as the prognosis may be worse than for non-transformed subtypes. https://crcp.tums.ac.ir/index.php/crcp/article/view/769