Growth of abnormal neurites in atypical Alzheimer's disease. A study with the Golgi method.

A cerebral biopsy was performed in a 39-year-old male patient with subacute paraparesis who later developed severe dementia and moderate cerebellar involvement. The histological examination showed a marked neuronal loss, severe neurofibrillary degeneration, and a great number of senile plaques. No PAS-positive plaques or amyloid angiopathy could be demonstrated. Golgi's sections showed (a) meshwork of fine dendrites located distally to the soma, (b) thick, coarse dendrites full of synaptic spines in neurons otherwise lacking these structures, and (c) thick dendrites with distal varicosities and filopodium-like processes resembling growth cones. These changes have been interpreted as acquired abnormal receptor sites and represent unique facts of a group of diseases not clearly defined, including atypical Alzheimer's disease and some cases of familiar Alzheimer's disease.