Parkinson Disease

Abstract

This cross-section of midbrain from an older man with a neurodegenerative disease exhibits marked pallor of the substantia nigra (arrow) compared with a normal brain. What is the most likely diagnosis and protein abnormality?a.Parkinson disease, α-synucleinb.Alzheimer disease, β-amyloidc.Frontotemporal dementia, taud.Amyotrophic lateral sclerosis, TDP-43 (TAR DNA-binding protein 43) Answer: a. Parkinson disease, α-synuclein Parkinson disease is characterized by bradykinesia, rigidity, stooped shuffling gate, and often resting tremor as well as nonmotor features such as anxiety, depression, and sleep disorders, among others.1Ahlskog J.E. Parkinson disease treatment in hospitals and nursing facilities: avoiding pitfalls.Mayo Clin Proc. 2014; 89: 997-1003Abstract Full Text Full Text PDF PubMed Scopus (13) Google Scholar The midbrain may exhibit pallor of the substantia nigra. Microscopic neuronal inclusions called Lewy bodies, a complex accumulation of proteins including α-synuclein, play a key role in the pathogenesis.2Dehay B. Bourdenx M. Gorry P. et al.Targeting α-synuclein for treatment of Parkinson's disease: mechanistic and therapeutic considerations.Lancet Neurol. 2015; 14: 855-866Abstract Full Text Full Text PDF PubMed Scopus (325) Google Scholar On hematoxylin and eosin stain (A), Lewy bodies appear as neuronal intracytoplasmic inclusions that are roughly spherical, eosinophilic, and surrounded by a pale “halo” (arrow). Lewy bodies are highlighted by the immunohistochemical stain for α-synuclein (B).