Primary cerebral lymphoma is a unique and infrequent CNS malignancy in which the B lymphocyte subtype constitutes most cases.1 B cell neoplasms other than multiple myeloma including non-Hodgkin’s lymphomas, and acute and chronic leukaemias might also exhibit lytic bone lesions, hypercalcaemia, and monoclonal gammopathy via the particular actions of interleukin (IL-1), IL-6, or tumour necrosis factor-α secreted by the neoplastic B cell clone, but not reported previously secondary to a primary cerebral lymphoma.2 We describe an unusual presentation of a B cell primary cerebral lymphoma mimicking a plasma cell dyscrasia.

A 64 year old woman was admitted with complaints of headache, ataxia, and urinary incontinence. Physical examination disclosed motor dysfunction in the legs, dysphasia, and impaired cerebellar function. On initial evaluation, a mass of 6×4 cm in diameter was shown in the left frontal lobe …