Treatment with a Direct Oral Anticoagulant for Nonbacterial Thrombotic Endocarditis

We herein report a case of nonbacterial thrombotic endocarditis (NBTE) in a patient with previously undiagnosed lung cancer. A 62-year-old woman presented to our hospital with multiple cerebral infarctions. There was no evidence of valvular heart disease or vegetations. Whole-leg ultrasonography revealed deep vein thrombosis of the left peroneal vein. We administered direct oral anticoagulants (DOACs) for a presumed diagnosis of paradoxical embolisms caused by patent foramen ovale. Unfortunately, she experienced further embolization and died. At a postmortem examination, she was diagnosed with NBTE and metastatic adenocarcinoma of the lung. Our experience with this patient suggests that DOACs may be an insufficient treatment for NBTE.