Rationale:Few isolated case reports and case series have reported arterial and venous thromboembolism related to adenomyosis; however, the underlying mechanism remains unclear.Patient concerns:A 47-year-old woman presented with dizziness, nausea, vomiting, and loss of consciousness after red blood cell transfusion. She was being treated for menorrhagia and severe anemia.Diagnoses:Magnetic resonance imaging showed multiple infarctions in right cerebellum and bilateral frontal, parietal, and occipital lobes. Echocardiography performed during the evaluation for the source of emboli revealed multiple echogenic masses on the tricuspid aortic valve. There was no evidence of infection, and the masses on the aortic valve were diagnosed as nonbacterial thrombotic endocarditis. The levels of autoimmune antibodies and tumor markers except for carbohydrate antigen 19-9 and cancer antigen 125 were within the normal range. Uterine ultrasound showed a large adenomyosis. The patient was diagnosed with multiple cerebral and cerebellar infarctions due to nonbacterial thrombotic endocarditis, and hormone therapy and anticoagulation with warfarin were initiated.Interventions:The patient did not develop recurrent infarction during anticoagulant therapy; however, menorrhagia worsened requiring total hysterectomy.Outcomes:The patient did not experience recurrent infarction despite the absence of anticoagulant therapy during the 3-year follow-up period.Lessons:The present case adds to the limited number of previously reported cases and supports that, albeit rare, adenomyosis can be associated with embolic infarction and suggests that nonbacterial thrombotic endocarditis might be the link between adenomyosis and embolic infarction.