Primary Central Nervous System Lymphoma (PCNSL) - A Rare and Unusual Presentation of Rapidly Progressive Major Cognitive Dysfunction.

Primary central nervous system lymphoma (PCNSL) is a rare, extranodal non- Hodgkin's lymphoma confined to craniospinal axis. PCNSL accounts for less than 5% of all primary CNS malignancies and 1 to 2% of all lymphomas. Amongst the causes of major cognitive dysfunction, primary brain tumor exists as a less frequent cause. We report a case of PCNSL as a rare and unusual presentation of rapidly progressive cognitive dysfunction which revealed clinicopathoradiological correlation. The patient revealed clinicoradiologically evident marked improvement after treatment, ascribing PCNSL as potentially reversible cause of major cognitive dysfunction.