Case report on right ventricular mural endocarditis, not diagnosed clinically, but histopathologically after cardiac surgery.

Background: Right ventricular mural endocarditis (RVME) is an extremely rare type of infective endocarditis that can occur even in the absence of predisposing factors. The diagnosis is a challenge when no causative pathogen can be detected. Case summary: A previously healthy young man was admitted to a local hospital with a diagnosis of prolonged febrile syndrome and treated for acute sinusitis. As complaints returned, he was hospitalized 3 weeks later, where an echocardiogram demonstrated multiple mobile masses in the right ventricle, and a computed tomography scan revealed extensive pulmonary thromboembolism. During surgery, the endocardial masses were excised, and the pathologist considered an inflammatory myofibroblastic tumour. Despite appropriate medication and initial improvements, the complaints persisted, and 2 weeks after the surgery, the patient returned to the hospital. Imaging studies documented reappearance to the previous findings, whereas blood cultures remained negative. During the second surgery, the new masses resembling vegetations were excised, and histologic analysis indicated infective endocarditis. Adjusted medication was given for 30 days. Just before discharge, no vegetations were seen. At follow-up, 5 years later, he was in a healthy condition. Discussion: Despite careful examinations, initial treatments according to standard protocols were unsuccessful. At final discharge, the patient reported that a tattoo complication prior to the first hospitalization was treated by antibiotics but that he did not complete the course. This omission in the communication further complicated the diagnostic and management processes, leading to surgical interventions that could have been prevented if the neglected antibiotic course was properly disclosed.