Sporadic amyotrophic lateral sclerosis of long duration mimicking spinal progressive muscular atrophy exists: Additional autopsy case with a clinical course of 19 years

This report concerns an autopsy case of sporadic amyotrophic lateral sclerosis (ALS) clinically diagnosed as having spinal progressive muscular atrophy (SPMA). The patient was a Japanese woman without hereditary burden. She developed muscle weakness in the distal part of the right upper extremity at age 52, followed by muscle weakness in the left upper extremity and lower extremities at age 54 and 64, respectively. At age 66 she could not walk, even with assistance. Fasciculation and atrophy of the tongue appeared at age 68, followed by dysphagia and dysarthria at age 70. She died of respiratory disturbance at age 71. During the clinical course, neurological examination revealed neither Babinski sign nor hyperreflexia. No respirator administration was performed throughout the clinical course. Neuropathological examination disclosed not only neuronal loss with gliosis in the hypoglossal nucleus and anterior horns of the spinal cord, but also loss of Betz cells and degeneration of the pyramidal tract. Based on these clinicopathological findings and a literature review of sporadic autopsy cases of ALS with long clinical course (10 years or more), including four cases without pyramidal signs, we believe that sporadic ALS of long clinical course mimicking SPMA exists.