By light microscopy, Hirano bodies are fusiform or spheroidal eosinophilic bodies, that are commonly observed in the hippocampi of the elderly and are especially numerous in patients with various dementias or degenerative diseases. Rarely, they have been demonstrated in other locations and even in animals. Ultrastructurally, the Hirano bodies are complex pleomorphic aggregates of intraneuronal fibrillary material found predominantly in the processes but occasionally in the perikarya. The Hirano bodies are assembled from multiple subunits, but occasionally in the perikarya. The Hirano bodies are assembled from multiple subunits, each consisting of two overlapping or intersecting expanses of parallel filaments. Depending on the plane of section and orientation, the subunit may appear as a lattice-work array of intersecting filaments, a row of regularly spaced punctate densities closely applied to a filament, or a broader feathery fibril. The subunits appear to be derived from the reorganization or precipitation of randomly dispersed finely filamentous material. Because of the diverse circumstance under which they are found, Hirano bodies are regarded as a non-specific manifestation of neuronal degeneration.
Hirano Bodies Rod-Like Structures Inclusions Electron Microscopy