Membranous cytoplasmic bodies in a patient with amyotrophic lateral sclerosis with short clinical duration

Abstract

Recently membranous cytoplasmic bodies (MCB) were observed in spinal anterior horn neurons in two patients with sporadic amyotrophic lateral sclerosis (ALS). Membranous cytoplasmic bodies are considered to be lysosomal in nature, therefore the abnormalities in the lysosomal system in ALS were emphasized in the report. We also observed abundant MCB in the lumbar anterior horn neurons in a sporadic ALS patient with short clinical duration. The neurons with MCB were densely packed with 10 nm neurofilaments, ribosome‐like granules, lipofuscin granules and other intracytoplasmic organelles without any distinctive inclusions. They appeared to show simple atrophy or chromatolysis upon light microscopy. By comparison, the ubiquitin reactive inclusion‐laden neurons showed fewer MCB. We speculate that in some ALS cases with short clinical duration the degenerative neurons have some abnormalities or overload of the lysosomal proteolytic systems leading to development of MCB.