An autopsy case of a 76-year-old woman with progressive supranuclear palsy initially presenting with dropped head and clinical features of pure akinesia with gait freezing

We present a case of a 76-year-old woman diagnosed with pathologically confirmed progressive supranuclear palsy (PSP) with pallido-nigral-luysial atrophy, who initially presented with a dropped head. Upon her first visit, neurophysiological and neuroradiological examinations provided no definitive cause, and the tactile trick was effective, leading to a diagnosis of cervical dystonia. Trihexyphenidyl treatment had no effect, but her condition gradually improved over 3 years. By age 74, she developed gait freezing without muscle rigidity or tremor. Dopamine-transporter scintigraphy revealed reduced tracer uptake in the bilateral corpus striata, prompting the diagnosis of pure akinesia with gait freezing (PAGF). At age 76, the patient developed retrocollis, muscle rigidity in all extremities, and recurrent temporomandibular dislocation. She eventually died from aspiration pneumonia after several years of illness. At autopsy, the brain weighed 1,370 ‍g. Macroscopic examination showed atrophy of the pallidum and subthalamic nucleus and depigmentation of the substantia nigra. Histopathological analysis revealed degeneration with 4-repeat tau pathology in the substantia nigra, globus pallidus, and subthalamic nucleus, along with tufted astrocytes in the globus pallidus and putamen, confirming a pathological diagnosis of pallido-nigral-luysial atrophy-type PSP. We suggest that the clinical presentation of PAGF correlates well with the pathological findings of pallido-nigral-luysial atrophy. While dystonia in PSP is typically observed in the limbs, blepharospasm, or retrocollis, only two other cases of PSP with a dropped head have been reported. The pathophysiological mechanism remains unclear, but we hypothesize that 4-repeat tau pathology in the globus pallidus may contribute to the development of cervical dystonia. Further neuropathological studies are needed to confirm this hypothesis.