Slowly progressive Parkinson syndrome due to thalamic butterfly astrocytoma.

A 74-year-old man had a 4-year history of slowly progressive asymmetric resting tremor, hypokinesia, rigidity, and postural instability and mild cognitive decline, initially diagnosed as Parkinson disease. Clinical response to levodopa was moderate (video on the Neurology Web site at www.neurology.org). Additional pyramidal signs developed; cranial MRI showed a symmetric bilateral tumor of the thalamus and brainstem (figure, A and B). Biopsy revealed an anaplastic astrocytoma grade III (figure, C). Even though parkinsonism caused by a tumor is rare,1 brain imaging should be considered early when presenting with atypical clinical signs or poor levodopa response, so as to exclude potentially treatable structural causes.