NQ-116: (B)
Pick’s body
Diagnosis: Pick's disease
Pathology of the case: Pick bodies are tau positive and silver stain positive. This feature distinguish them from other entities in the family of frontotemporal dementia. [Click here to see silver stain, immunohistochemistry for tau and ubiquitin]
Pick disease is a frontotemporal lobar degeneration (FTLD-Pick) characterized clinically by marked behavioral and personality changes in conjunction with difficulty in language. Pick disease results in striking neuronal loss with subsequent atrophy involving the temporal lobes, with sparing of the superior temporal gyrus. The atrophy can be so severe as to give the atrophic gyri a “knife’s edge” appearance. The overall weight of the brain may be markedly decreased from the atrophy. Microscopically, neurons contain amphophilic to eosinophilic cytoplasmic inclusions (arrow) that are the result of the accumulation of 3-repeat (3R) tau. Immunohistochemical staining for tau will be positive in these inclusions.
Lewy bodies are also eosinophilic cytoplasmic inclusions but they are the result of accumulation of synuclein. They will be negative for tau, but positive for alpha-synuclein. Lewy bodies are seen in Lewy body dementia, Parkinson disease, etc.
Pale bodies are eosinophilic cytoplasmic inclusions that may be seen in the pigmented neurons of the substantia nigra or locus ceruleus that are thought to represent early Lewy bodies.
Hirano bodies are intracellular accumulations of actin and actin-associated proteins within neurons of the hippocampus. While they may be seen in patients with Alzheimer disease, they are not diagnostic of this disease. They appear as rod-like eosinophilic inclusions that may appear spherical when cut in cross section. They are negative for tau staining.
Polyglucosan bodies are accumulations of glycogen within the cytoplasm of neurons in patients with adult polyglucosan body disease, a glycogen storage disorder. The accumulations will also occur in other organs and axillary skin biopsy may be diagnostic. These inclusions will be negative for tau.