The definitive histological hallmark of Parkinson disease on autopsy is:

• A Neurofibrillary tangles in the substantia nigra neurons
• B Pick bodies in frontal lobe neurons
• C Lewy bodies — eosinophilic intracytoplasmic inclusions composed of aggregated alpha-synuclein in substantia nigra neurons ✓
• D TDP-43 inclusions in motor neurons of the spinal cord

Explanation

Lewy bodies are eosinophilic, round intracytoplasmic inclusions with a dense core and pale halo, composed primarily of aggregated alpha-synuclein (and ubiquitin). They are found in surviving neurons of the substantia nigra pars compacta and are pathognomonic of Parkinson disease. Neurofibrillary tangles (hyperphosphorylated tau) characterize Alzheimer disease; Pick bodies (tau) characterize frontotemporal dementia; TDP-43 inclusions characterize ALS and FTLD-TDP.

Reference: Robbins & Cotran Pathologic Basis of Disease, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.