Primary central nervous system lymphoma presenting with a parkinsonian syndrome of pure akinesia.

The incidence of primary central nervous system lymphoma (PCNSL), once a rare tumour, has risen significantly in both immunocompetent and immunosuppressed patients. Although infiltration of the basal ganglia is not uncommon in PCNSL, extrapyramidal movement disorders are generally not recognised as a mode of clinical presentation of this type of cerebral tumour. We present the unusual case of a 75-year-old man who developed a parkinsonian syndrome of "pure akinesia" due to autopsy-confirmed PCNSL primarily involving the globus pallidus bilaterally. Parkinsonism due to bilateral pallidal lesions is known but rare, and such cases help in the understanding of basal ganglia function with regard to akinesia and freezing.