Primary cardiac myxofibrosarcoma in a patient with Ebstein's anomaly: First reported case

Primary Cardiac Myxofibrosarcoma (PCM) is a rare and aggressive cardiac malignancy, accounting for less than 1 % of primary cardiac tumors. It can occur infrequently with congenital heart defects like Ebstein's anomaly (EA), characterized by a malformed tricuspid valve. PCM often presents as a painless cardiac mass, leading to potential delays in diagnosis and treatment.

We present the case of a 38-year-old female with a history of EA who presented with dyspnea. Echocardiography revealed severe tricuspid regurgitation and a mobile mass in the left atrium, which prolapsed through the mitral valve with each heartbeat. Intraoperative findings confirmed a lobulated mass. Histological analysis showed a multinodular spindle cell tumor within a myxoid stroma, featuring long, curvilinear blood vessels, few hypocellular myxomatous areas, and focal necrosis. Immunohistochemical staining revealed positivity for TLE1 and SMA, while the tumor was negative for AE1/AE3, S100, desmin, CD34, HMB45, and CD117, leading to a diagnosis of PCM.

Initially suspected to be a myxoma, histopathological findings confirmed PCM, notably characterized by prominent thin-walled blood vessels. This highlights the importance of thorough pathological evaluation. This case is the first reported instance of PCM associated with EA, contributing to the limited literature on this rare combination.

Malignant tumors should be included in the differential diagnosis of cardiac masses. Prompt diagnosis and complete surgical resection are essential for improving patient outcomes and reducing the risk of recurrence.