BACKGROUND: Non-valvular mural infective endocarditis (IE) is a rare bacterial growth on cardiac walls. Several risk factors have been reported. Echocardiography is an important diagnostic modality for diagnosing vegetation attached to the intracardiac walls.

CASE REPORT: We present the case of a 57-year-old man admitted with Staphylococcus aureus bacteremia due to an infected tunnelled hemodialyses catheter. Transthoracic echocardiogram did not show any abnormality, but transesophageal echocardiogram (TEE) revealed a 1.7×0.8 cm mobile echo-density attached to the surface of the interatrial septum in the left atrium, where the foramen ovale (FO) exists in utero. The patient was transferred to another facility for re-do sternotomy cardiac surgery, where these findings were confirmed intraoperatively. A biopsy of the mass was taken, which confirmed it to be a vegetation attached to the FO.

CONCLUSIONS: We report the first case in the literature of vegetation attached to the surface of the interatrial septum in the left atrium at the congenital location of the foramen ovale. There have been no previously reported cases in the literature with such novel imaging findings.

Keywords: Echocardiography, Transesophageal, Endocarditis, foramen ovale, Foramen Ovale, Patent