A Case of Malignant Lymphoma With Cerebral Intravascular Component Diagnosed at Autopsy With Repeated Stenosis of the Bilateral Anterior Cerebral Artery

Intravascular large B-cell lymphoma (IVLBCL) is a rare disease characterized by selective proliferation of lymphoma cells within the lumen of blood vessels, especially capillaries. When IVLBCL involves the central nervous system (CNS), it could cause a stroke. IVLBCL is often difficult to diagnose because the disease lacks specific imaging findings and symptoms and can sometimes progress rapidly. We report a rare case of IVLBCL with repeated stenosis and improvement of the bilateral anterior cerebral artery (ACA) that required a long time to diagnose. The patient was admitted to our hospital three times (days 1-22, days 126-171, and days 212-221) after ischemic stroke. After acute-phase treatment, the patient was transferred to a rehabilitation hospital but developed systemic symptoms such as diarrhea, dizziness, and vomiting with ischemic stroke and was transferred back to our hospital. Various examinations were performed, but the causes remained unknown. Malignant lymphoma was strongly suspected at the third hospitalization; however, before treatment was started, the patient died of a hemorrhagic stroke. An autopsy revealed a relatively large number of lymphoma cells in the small vessels of the subarachnoid space of the brain, consistent with IVLBCL. Because of repeated systemic symptoms and dynamic evolution of ischemic stroke with repeated stenosis of the bilateral ACA, some diseases were suspected to be the etiology of stroke; however, diagnosis was not made until the patient died, and follow-up was delayed because IVLBCL progressed aggressively. In addition to the aggressive and atypical clinical course, imaging findings of repeated stenosis of the bilateral ACA may help suspect IVLBCL.