A 60-year-old, hypertensive, heavy smoker, male presented in the emergency department (ER) with chest discomfort, bloody sputum, mild fever, and a swollen right lower limb. Α duplex scan of the limb performed initially was positive for deep vein thrombosis. Further work-up with ventilation–perfusion lung scintigraphy (VQ) confirmed the diagnosis of pulmonary embolism. As a result, the patient was treated with an anticoagulation regimen, with gradual symptom remission. Furthermore, a chest computed tomography (CT) scan was carried out, revealing a 15-mm nodule at the lingula and a few mildly swollen para-aortic lymph nodes. The transthoracic echocardiography (TTE) performed at that time only showed a mild aortic insufficiency. Therefore, the patient was discharged home with instructions to perform a new scan for follow-up of the lung nodule and an upper and lower gastrointestinal endoscopy, as well as to undertake a thrombophilia test.

A month later, he presented again in the emergency department, with general weakness and gait instability. A brain CT scan revealed a recent left temporoparietal infarct. High values of hs-Troponin-I and inflammatory markers were also noted in his laboratory tests. Another TTE was performed, and a perforated coronary cusp was noted, thus suggesting the diagnosis of endocarditis. The finding was further confirmed with transesophageal echocardiography (TEE). The coronary angiogram showed marginal lesions in the right coronary artery.

Few days later, a severe chest pain episode occurred with ST-segment elevations in the ECG, sharp rise of the Troponin levels, and anterior wall and apex motion abnormalities (WMA). A TTE finally revealed small vegetations in the aortic valve along with mild aortic insufficiency, in addition to the sustained apex WMA and regurgitation jets (Fig. 1). The diagnosis of infective endocarditis with embolic events in the brain and the coronary arteries was highly considered.

Aortic valve regurgitant jets seen in echocardiography

Multiple blood cultures, viral, immunological, and tumor marker tests (Roche SeptiFast® MGRADE PCR, Coxiella IgM and IgG antibodies, Widal-Wright test, lupus anticoagulant levels, b2-gpi antibodies, galactomannan antigen test, serum complement C3-C4, β-d-Glucan Test, Wright-Coombs test, and Coxsackie B antibodies) were all negative. Despite empirical antibiotic therapies, there was no remarkable clinical or serological change of state. In contrast, the patient’s condition deteriorated with fever, moderate renal failure, elevating inflammatory markers, and lower limb digit emboli. Additionally, a new CT scan revealed splenic infarcts. The patient fulfilled the modified Duke criteria for possible endocarditis (one major criterion—vegetations in the aortic valve) and two minor ones (fever and vascular phenomena) and was transferred to the Department of Cardiothoracic Surgery for urgent surgical management.

The rapid clinical deterioration and the multiple negative blood cultures despite a broad-spectrum antibiotic treatment posed a diagnostic dilemma. As a result, a fluorodeoxyglucose-positron emission tomography (FDG-PET) scan was conducted. The findings were conclusive: increased FDG uptake in numerous thoracic lymph node groups and the known lingula lesion but no uptake in the aortic valve (Figs. 2, 3, and 4).

PET-CT scan showing no FDG uptake at the aortic valve region

PET-CT scan showing increased uptake of FDG in multiple thoracic lymph node groups (prevascular anterior to the major vessels in upper mediastinum, para-aortic, left and right paratracheal, aorto-pulmonary window, subcarinal, and right and left hilar—SUVmax: 23,4)

PET-CT scan showing increased FDG uptake from the lingula lesion (SUVmax: 13)

After heart team consultation, the option of surgery was preferred for the replacement of the embologenic aortic valve and the biopsy of the mediastinal lymph nodes. So, an aortic valve replacement with a mechanical prosthesis and a resection of a para-aortic lymph node block was performed.

The native aortic valve had mild calcifications, no cusp destruction, and broad base small vegetations. The culture of the valve was negative, but the histological result of the lymph node block was solid/micropapillary lung adenocarcinoma. After this result, the diagnosis of marantic, non-thrombotic endocarditis was established.

A stormy postoperative course followed, including renal failure necessitating renal replacement therapy, and multiple brain infarcts due to disseminated intravascular coagulopathy, all of which led to the patient’s death 10 days postoperatively.