Dementia with Lewy bodies and additional progressive supranuclear palsy presenting with early postural instability and frequent falls: an autopsy case.

backgroundDementia with Lewy bodies (DLB) is characterized by fluctuating cognition, visual hallucinations, and Parkinsonism, whereas progressive supranuclear palsy (PSP) typically presents with supranuclear gaze palsy, postural instability, and akinesia or rigidity. Although they represent distinct pathological entities, comorbid Lewy body disease and PSP has occasionally been reported and may contribute to clinical heterogeneity. We report an autopsy case of comorbid DLB with mild PSP pathology, clinically manifesting as DLB with early onset falls, resulting in cerebral contusion and traumatic subarachnoid hemorrhage. CASE PRESENTATION: An 86-year-old patient developed progressive memory impairment 1 year before death, followed by cognitive fluctuations, visual hallucinations, and delusional speech. Two months before death, the patient required wheelchair assistance due to gait disturbances and frequent falls. Neurological examination revealed tremors and rigidity in both upper limbs. Computed tomography of the head revealed cerebral contusion, traumatic subarachnoid hemorrhage, and chronic subdural hematoma. The clinical presentation was consistent with that of DLB, although the patient experienced prominent falls and marked postural instability. The patient died at the age of 87, soon after initial consultation. Neuropathological analysis revealed the presence of Lewy bodies in the substantia nigra and amygdala, with α-synuclein pathology in the brainstem and limbic system, consistent with limbic-predominant DLB. Tau pathology, including neurofibrillary tangles and tufted astrocytes, was present in the frontal lobe, globus pallidus, putamen and midbrain tegmentum, fulfilling the diagnostic criteria for PSP, although the overall severity was mild. α-synuclein pathology was also identified in the midbrain tegmentum including the cuneiform nucleus, a key component of the mesencephalic locomotor region.

conclusionsThis case illustrates that comorbid DLB and PSP can produce an atypical phenotype showing core features of DLB, early severe postural instability, and frequent falls. We believe that dual involvement of tau and α-synuclein pathologies in the mesencephalic locomotor region in the midbrain tegmentum contributed to gait disturbances and falls, leading to cerebral contusion and traumatic subarachnoid hemorrhage.