[An autopsy case with lower motor neuron disease showing a transient-appearance of anti-GM1 antibody and an improvement of conduction block after gamma-globulin administration].

We report a 63-year-old man who died of respiratory failure. He was well until 1992 (57 years of his age), when he had an onset of progressive weakness of the bilateral upper limbs. He showed no improvement with TRH administration in other hospital. On January 12, 1994, he admitted to our department because of the progressive muscle weakness. Neurologic examination revealed a muscular atrophy associated with severe weakness and hyporeflexia in both upper limbs, and fasciculation were seen in his tongue. Electrophysiological studies revealed mild conduction block in the left medial nerve, and F-waves were not evoked in the left ulnar nerve and bilateral median nerves. After an administration of 25 g/day of human gamma-immunoglobulin for 5 days, conduction block as well as F-wave abnormalities in the left median and left ulnar nerve were improved, yet no improvement of muscle weakness was seen. The anti-GM1 IgG titer was transiently elevated in the patient's serum after gamma-immunoglobulin therapy. On September 8, 1994, subtotal gastrectomy was performed because of the early stage gastric cancer. Histological examination showed poorly differentiated adenocarcinoma (signet-ring cell carcinoma). His muscle weakness had been gradually extended to the lower limbs and he couldn't walk himself on January, 1998. On March, 1998, he developed tetraplegia, mild dysphagia, dysuria and the respiratory disturbance. On April 12, 1998, he admitted to our department for the second time. Neurologic examination revealed a muscular atrophy and fasciculation associated with severe weakness in all of his limbs, tongue and musclus masseter. Neither deep tendon reflex nor pathologic reflex was evoked in his upper and lower extremities. His ocular movements and sensations were well preserved. He died of respiratory failure on May 1, 1998. The patient was presented in a neurological CPC. Neurological and laboratory findings suggested a spinal progressive muscular atrophy (SPMA). However, there were several unusual points as a typical SPMA in this case, that is, an improvement of the electrophysiological abnormalities by gamma-globulin treatment, as well as transient elevation of anti-GM1 antibody. The clinical neurologists have arrived at the conclusion that the patient had lower motor neuron syndrome associated with anti-ganglioside antibody and cause of death was ascribed to the respiratory failure. We discussed whether this case was SPMA or multifocal motor neuropathy. Postmortem examination revealed numerous diverticulums in the ascending colon and lymphothyroiditis. No recurrent carcinoma was detected. Neuropathologically, both severe atrophy of the anterior spinal roots, and severe gliosis and neuronal loss in the anterior horn of the spinal cord were observed. Onuf nuclei were not affected. Neurogenic muscular atrophy was detected in the tongue, diaphragm, and limb muscles. Motor neurons of the brainstem were relatively preserved, but skein-like inclusions as detected by anti-ubiquitin antibody, were present in the facial and hypoglossal nuclei. Neither motor cortex nor cortico-spinal tracts were affected. Demyelination, remyelination or cellular infiltrations were not apparent in the right median nerve and sciatic nerves. The neuropathologic features were compatible with SPMA.