Teaching NeuroImages: pseudo-abnormal DaTscan findings in meningioma-induced parkinsonism

A 71-year-old man presented with a 6-month history of rest tremor and slowness in his left hand. Apart from mild left parkinsonism, neurologic examination was unremarkable. Because response to l-dopa, up to 600 mg/d, was lacking, [123I]FP-CIT (123I- N -ω-fluoropropyl-2β-carbomethoxy-3β-[4-iodophenyl]nortropane) SPECT was prescribed with unexpected results: transverse and coronal slices showed the right striatum to be moved upward and medially, suggesting a structural compression rather than degenerative damage (figure). Brain MRI revealed the presence of a frontal meningioma. Caution is required when interpreting DaTscan findings,1,2 and morphologic imaging should always be performed first.