Recurrent Natural Killer Cell Lymphoma with Central Nervous System Metastasis Mimicking Cerebellar Infarction

Background Natural killer cell lymphoma is an uncommon hematologic malignancy, and central nervous system metastasis is rare. The classic magnetic resonance imaging appearance of lymphoma in the brain is T1 hypointense with strong homogeneous gadolinium enhancement, variable T2 signal, and restricted diffusion on diffusion-weighted images. Gadolinium enhancement is an important feature to differentiate lymphoma from infarction. Case Description We present the case of a middle-aged man who presented with recurrent natural killer cell lymphoma that metastasized to the cerebellum. Computed tomography and magnetic resonance imaging did not show a contrast-enhancing lesion; imaging features were more suggestive of cerebral infarction. The patient subsequently died, and postmortem examination confirmed natural killer cell lymphoma metastasis to the cerebellum. Conclusions Lymphoma can mimic cerebral infarction on computed tomography and magnetic resonance imaging. An imaging appearance of cerebral infarction in a patient with a history of lymphoma should raise suspicions of lymphoma metastasis.