Primary CNS lymphoma as a cause of Korsakoff syndrome.

BACKGROUND: Korsakoff syndrome presents with memory dysfunction with retrograde amnesia, anterograde amnesia, limited insight into dysfunction, and confabulation. The most common etiology of Korsakoff syndrome is thiamine deficiency secondary to alcoholism. There are limited case reports of structural lesions causing Korsakoff syndrome.

CASE DESCRIPTION: A 46-year-old male with a long history of alcoholism presented with a history of confusion, amnesia, and confabulation with no localizing features on neurological examination. The patient showed no clinical change with intravenous thiamine. Computed tomography of the brain revealed a heterogenous, enhancing mass lesion centered within the third ventricle, with other lesions found throughout cortical and subcortical regions. The patient was given dexamethasone i.v. without noticeable clinical improvement but with marked radiological improvement with mass reduction. Stereotactic biopsy revealed a diagnosis of primary central nervous system (CNS) lymphoma.

CONCLUSIONS: Most patients presenting with Korsakoff syndrome have thiamine deficiency; however, mass lesions can produce an identical clinical picture. This is the first case report of a patient with primary CNS lymphoma presenting as Korsakoff syndrome.