Abstract
Patient presentation
During a routine check up, a 47yo man with Tetralogy of Fallot and congenital absence of left pulmonary branch was found to have a vegetation on his prosthetic pulmonary valve. His surgical history included TOF repair with left pulmonary branch bypass aged 4 years and a redo surgery for pulmonary valve replacement 3 years earlier. Before last surgery, CMR showed severe pulmonary regurgitation, dilated RV with mildly impaired systolic function (EF 40%) and absent flow in left pulmonary branch due to bypass occlusion.
Diagnostic work-up
The patient reported increasing shortness of breath (NYHA class III) over the last months. He reported one single fever peak two months before.He was on Apixaban and Amiodarone for previous history of AF. He was afebrile and an ejective systolic 4/6 murmur was heard. He was in sinus rhythm at 70 bpm. The TTE showed dilated RV with severely reduced systolic function (FAC 12%), severe pulmonary stenosis (peak gradient of 70 mmHg) with mild regurgitation, and a mobile and echogenic vegetation of 10 X 9 mm was seen on the prosthetic pulmonary valve. His blood tests at the admission demostrated raised WBC (9.460/uL) and PCR 11.7 mg/dl (n.v. < 3.0). The PCR remained stable during the following days. Serial blood samples for cultures were obtained, but all resulted negative. Uncommom causes of negative blood culteres infective endocarditis were investigated with specific serological tests for research of fastious agents, but all resulted negative. Antinuclear and antiphospholipid antibodies were also tested. A total-body CT was performed and it showed several liver formations. A FDG PET-CT was requested and it demostrated active marked glucose uptake by a mediastinic node, as well as by liver, brain and prosthetic pulmonary valve.
Diagnosis and outcome
After a careful review of all the clinical and imaging data, our opinion was that the most probable diagnosis was non infective thrombotic endocarditis in patient with metastatic cancer. In this situation, the valvular glucose uptake was likely due active thrombus formation rathen then being a sign of inflammatory response. Unfortunately, the patient died suddenly two weeks after the PET-CT and it was impossible to confirm the diagnosis with biopsy.
Conclusion
Differential diagnosis of cardiac vegetations is a challenging process including microbological tests, multi modality imaging and clinical reasoning. It is always necessary to consider alternative diagnosis, even when traditional imaging tests seem to suggest infective endocarditis.
Non infective thrombotic endocarditis are a rare form of negative blood culteres endocarditis related to systemic hypercoagulable state (i.e. antiphospholipid syndrome, systemic lupus, behcet syndrome, cancer). Malignancies can be considered an unusual cause of cardiac vegetation and they must be taken into account on differential diagnosis.
Abstract 1107 Figure. FDG uptake in pulmonary position
Osteosarcoma with cytokeratin expression: a clinicopathological study of six cases with an emphasis on differential diagnosis from metastatic cancer
