Primary central nervous system lymphoma presenting as choreoathetosis.

To cite: Noda K, Hattori N, Okuma Y. BMJ Case Rep Published online: [please include Day Month Year] doi:10.1136/bcr-2013203353 DESCRIPTION A 49-year-old man developed right hemiparesis and choreoathetosis involving his right upper and lower extremities. His choreoathetosis worsened with attempts at action or posture. Neurological examination showed mild dysarthria, and right upper motor neuron facial palsy. His gait was almost normal. There was no loss of pain sensation or proprioception. Brain MRIs showed high-intensity areas in the left cerebral peduncle, subthalamic nucleus, thalamus and adjacent posterior limb of internal capsule (PLIC) on fluid-attenuated inversion recovery images (figure 1). Coronal T1-weighted images showed contrast-enhancing lesions in PLIC that extended into the cerebral peduncle (figure 2). A brain biopsy revealed a primary central nervous system lymphoma (PCNSL) of the diffuse large B-cell type. The patient was started on three cycles of methotrexate-based chemotherapy followed by whole-brain radiotherapy at a dose of 56 Gy including a boost to the tumour site showing radiological responses. His movement disorders completely resolved following the treatment. In an MRI study of PCNSL at presentation, 15.7% of all lesions involved the basal ganglia and thalamus. Furthermore, choreoathetosis associated with PCNSL are uncommon. Poewe et al reported the case of a patient presenting with arm chorea due to lesions in the contralateral caudate, putamen, a large part of the thalamus and the subthalamic nucleus. Tan et al reported the case of a patient with isolated choreoathetosis due to lesions in the globus pallidus and subthalamic nucleus, extending into the substantia nigra. In this patient, his choreoathetosis may be due to the interruption of the basal ganglia-thalamocortical circuitry.