Post-polio syndrome (PPS) characterized by new neuromuscular problems can appear many years after acute poliomyelitis in polio survivors. We report a 77-year-old man with antecedent poliomyelitis who newly developed neuromuscular disease with a clinical course of 27 years, the final 10 years of which were characterized by apparent progression, thus raising doubt as to the clinical diagnosis of amyotrophic lateral sclerosis (ALS) following PPS. Pathologically, plaque-like, old poliomyelitis lesions were found almost exclusively in the lumbosacral cord, showing complete neuronal loss and glial scars in the anterior horns. Although less severe, neuronal loss and gliosis were also evident outside the old lesions, including the intermediate zone. Moreover, symmetrical degeneration of the corticospinal tracts, as evidenced by CD68 immunostaining, was a feature of the white matter of the lower spinal cord. In the motor cortex, loss of Betz cells was also confirmed. Synaptophysin immunostaining of the lumbosacral cord also revealed decreased expression outside the old lesions, excluding the posterior horn. Interestingly, decreased expression of synaptophysin was also evident in the cervical anterior horns, where no old lesions were observed. No Bunina bodies, TDP-43 inclusions, or Golgi fragmentation were found. Neurogenic atrophy was evident in the iliopsoas and scalenus muscles, and inclusion body myositis-like changes were also observed in these muscles and the tongue. Was it possible to have diagnosed this patient as having ALS? We consider that the features in this case may have represented the pathology of long-standing and/or fatal PPS itself, and not ALS.
© 2012 Japanese Society of Neuropathology.