Multimodality Imaging and Pathology of an Incidentally Discovered Right Atrial Myxoma Arising from the Crista Terminalis

Cardiac myxomas are the second most common benign cardiac tumor in adults. Most arise from the interatrial septum in the left atrium. Although most patients present with cardiac or embolic symptoms, some lesions are detected incidentally at imaging performed for unrelated indications. This case report describes the incidental discovery of a right atrial mass partially visualized at CT of the abdomen and pelvis during workup for cholecystitis. Subsequent multimodality imaging demonstrated a right atrial mass arising from the crista terminalis, which was confirmed to be a myxoma at pathologic examination. This case highlights an atypical origin and location of a common cardiac tumor incidentally detected at abdominal imaging. Keywords: Pathology, Neoplasms-Primary, Right Atrium, Heart, Cardiac, Ultrasound, MR Imaging, CT Angiography, CT © RSNA, 2026.