We present a biopsy-confirmed case of intravascular large B-Cell lymphoma (IVBCL) which was initially diagnosed as internal border-zone hypo-perfusion infarcts. Recognition of this previously undescribed feature of IVBCL is critical to early diagnosis and optimal patient care. 

A 53-year-old man was seen in a local ER for behavioral changes and left sided weakness. MRI of the head with contrast showed multiple small infarcts within the deep and periventricular bilateral cerebral white matter, typical of internal border-zone hypo-perfusion infarcts. TEE, hypercoagulable tests, LP and IR angiogram were unremarkable. He was treated as a hypo-perfusion injury and discharged home. Patient returned to ER three days later with worsening left sided weakness. Repeat brain MRI showed new areas of restricted diffusion within the internal border-zones. Intravascular lymphoma was suggested based on the MRI findings. This prompted a brain biopsy and subsequent confirmation of intravascular lymphoma by pathology. 

Typical neuroimaging features of IVBCL include linear and nodular enhancement and/or restricted diffusion within the deep and periventricular cerebral white matter and basal ganglia. Typical enhancing features may be absent and up to 36 % of IVBCL cases present with multifocal infarcts with a predilection for the cerebral white matter.  However, an imaging appearance that specifically mimics “internal border zone” infarcts has not been previously described.  Internal border-zone infarcts typically result from hypotension in the setting of carotid occlusive disease or severe stenosis such as moyamoya. IVBCL has a predilection for small perforating arteries which contain the lowest perfusion pressure. Accordingly, infarcts associated with IVBCL can result in the same MR appearance as hypoperfusion infarcts in the setting of moyamoya or carotid occlusive disease. Recognition of this mimicking feature of IVBCL is critical for optimal patient management. Our patient is currently in remission.