A neuropathologist is performing an autopsy on a 65 year old man who had resting tremor, rigidity, and akinesia. Histologic sections of the substantia nigra reveal neurons containing round eosinophilic inclusions. Such inclusions most likely represent?

This item lists a number of characteristic inclusions found in pathologic conditions of the CNS. The trick here is to first identify the classic triad of Parkinson disease (namely, tremors, rigidity, and akinesia), then recognize its typical histopathologic hallmark: round, eosinophilic, intracytoplasmic inclusions seen in neurons of substantia nigra. Lewy bodies are filamentous inclusions that appear brightly eosinophilic on hematoxylin and eosin stain and accumulate in the cytoplasm of dopaminergic neurons in the substantia nigra in Parkinson disease. All the other inclusions listed in the answer choices have different pathologic significance. Granulovacuolar degeneration and Hirano bodies are intracytoplasmic inclusions found in hippocampal pyramidal neurons of Alzheimer patients and intellectually intact elderly people. Lafora bodies contain polyglucosan and are found in neurons, glial cells, sweat glands, liver, and skeletal muscles in patients with the rare Lafora disease. Ref: Olanow C.W., Schapira A.H. (2012). Chapter 372. Parkinson's Disease and Other Movement Disorders. In D.L. Longo, A.S. Fauci, D.L. Kasper, S.L. Hauser, J.L. Jameson, J. Loscalzo (Eds), Harrison's Principles of Internal Medicine, 18e.