Primary intravascular large B-Cell lymphoma of the central nervous system - Antemortem diagnosis and review of literature

Intravascular large B-cell lymphoma (IVLBCL) is a rare type of extranodal large B-cell lymphoma occurring in adults, characterised by growth of neoplastic lymphoid cells within the lumina of blood vessels, particularly capillaries. The clinical presentations are non-specific and histological features are often subtle. We report a case of a 60-year-old male who presented with a several week history of headaches, general malaise and fluctuating visual disturbances followed by sudden onset of confusion. Neurological deficits included disorientation, nominal aphasia, left-right disorientation and left sided homonomous hemianopia. MRI of the brain revealed diffuse leptomeningeal enhancement and digital subtraction angiography showed an abnormality of a branch of the left of middle cerebral artery consistent with CNS vasculopathy. The differential diagnosis included vasculitis, stroke and atypical migraine necessitating an open biopsy. The histological sections revealed an intravascular infiltrate of large neoplastic B-cells that express CD20 within leptomeningeal vessels and small intrapar-encymal vessels with no involvement of the brain parenchyma. The case illustrates the protean clinical manifestations of CNS IVLBCL and the subtleties of its histological diagnosis. Correct diagnosis is important as treatment regimes drastically differ between IVLBCL and its clinical mimics.