Olfactory bulb involvement in Pick's disease.

The olfactory bulbs and stalks were examined in a case of Pick's disease that showed numerous and widespread Pick bodies in the brain. Typical argyrophilic inclusions (Pick bodies) were found not only in many cells of the anterior olfactory nucleus by also in some mitral cells and tufted cells. In addition, neuronal loss and astrocytosis were evident. No neurofibrillary change or senile plaque were detected anywhere in these structures. Electron microscopy disclosed that there was no ultrastructural difference between Pick bodies in the olfactory bulb and those in the cerebral cortex or hippocampus. These data indicate that in Pick's disease mitral cells and tufted cells, as well as anterior olfactory nucleus cells, are affected by degeneration specific to Pick's disease.