Intravascular large cell lymphoma (IVLCL) is a rare disease characterized by proliferation of malignant lymphocytes within the small blood vessel lumens. The association of IVLCL with autoimmune hemolytic anemia (AIHA) has been described in a single case report, but the true prevalence of this co-occurrence is not known because of declining autopsy rates. Here, we report a case of a 41-year-old woman who carried a diagnosis of AIHA for 2 years, with repeated hemolytic episodes that were initially well controlled with immunomodulatory treatment. At her last presentation, the patient developed rapidly progressive neurologic symptoms and leukoencephalopathy on MRI; she died 4 weeks later with a clinical impression of thrombotic microangiopathy, a known complication of AIHA. At autopsy, the brain showed widespread platelet thrombi and intraparenchymal hemorrhages characteristic of this disorder. In addition, there was evidence of a clinically unsuspected IVLCL, most likely of B-cell lineage. This case illustrates a potential association between IVLCL and AIHA, highlights the need for broad differential diagnosis in cases with atypical disease presentation or progression, and underlines the importance of autopsy in establishing the full cause of morbidity and mortality.