A Giant Eustachian Valve Protruding Into the Right Ventricle: A Case Report

The Eustachian valve (EV) remnant, when present in adults, is usually rudimentary. However, in echocardiographic examinations, it may appear as a mobile long structure in the right atrium, and it rarely protrudes into the right ventricle. When it is quite large, the EV remnant could be misdiagnosed as a right atrial tumor, thrombus, or vegetation. An 83-year-old patient was referred to the surgical ward for the excision of a gastric adenocarcinoma. In the course of preoperative assessment, transthoracic echocardiography showed a right atrial mobile filamentous mass that was protruding into the right ventricle. Differential diagnosis included a tumor or thrombus. After a precise evaluation through multiple views, the mass was demonstrated to be a giant EV, 7.3 cm in length. The giant EV remnant can persist in adults and is often diagnosed incidentally via echocardiography. Transthoracic echocardiography is a reliable noninvasive method for the diagnosis of the EV remnant and could help avoid its misdiagnosis as a tumor or thrombus. Nevertheless, sometimes transesophageal echocardiography is necessary to confirm the diagnosis or to demonstrate the existence of an additive clot on it.