Mesial Frontal Lobe Infarction Presenting as Pisa Syndrome.

Pisa syndrome is usually seen in patients with Alzheimer's disease treated with a cholinesterase inhibitor, dementia with Lewy bodies, Parkinson's disease, or atypical parkinsonism including multiple system atrophy. An 86-year-old woman presented with an acute onset of lateral flexion of her trunk to the left side, i.e., Pisa syndrome. She also showed left hemiparesis predominantly in her lower extremity. Her diffusion-weighted magnetic resonance images showed acute infarction in the right premotor area and supplementary motor area. Clopidogrel (75 mg daily) was prescribed. After two weeks from the onset of symptoms, her Pisa syndrome improved. The pathophysiology of Pisa syndrome has not yet been fully understood, but different mechanisms have been assumed. In this patient, it is possible that the infarction in her unilateral frontal lobe impaired the information processing from the temporoparietal cortex to the frontal lobe, including the premotor area and supplementary motor area for anticipatory postural control.