PET-scan in diagnosis of non-bacterial thrombotic endocarditis: a case report

Non-bacterial thrombotic endocarditis (NBTE), also known as marantic endocarditis or Libman-Sacks endocarditis, is a rare non-infectious condition affecting mostly the left-sided heart valves of patients who, most often, suffer from malignancies and connective tissue disorders. Herein, we present a case of a male patient with marantic endocarditis due to occult lung adenocarcinoma.

The patient fulfilled the modified Duke's criteria of possible bacterial endocarditis of the aortic valve; however, multiple blood cultures and serological tests were negative. In addition, the patient's clinical course was constantly deteriorating. Thus, a fluorodeoxyglucose-positron emission tomography (FDG-PET) scan was conducted. This examination revealed multiple positive thoracic lymph node groups, as well as a positive lung lesion. The patient underwent aortic valve replacement and lymph biopsies during the operation established the diagnosis of solid/micropapillary lung adenocarcinoma and consequently of the non-bacterial thrombotic endocarditis.

Advanced imaging techniques may be needed to diagnose NBTE and should be kept in mind when the Duke criteria are not definite. Clinical suspicion is key to implement these premises. However, the exact role of the PET-scan has yet to be specified.