Forme fruste or incipient form of widespread-type amyotrophic lateral sclerosis, or motor neuron disease with pallido-nigro-luysian atrophy? An autopsy case report.

We describe a 52-year-old man with body weight loss and bulbar palsy, who exhibited muscle atrophy and weakness with fasciculation especially in the respiratory muscles 4 years prior to death, necessitating respiratory support for 4 years, but who was able to walk until the end-stage. He had no significant family history. Neuropathological examination revealed severe loss of motor neurons in the spinal cord and brainstem, and ubiquitin-positive skein-like inclusions and Bunina bodies in the remaining neurons. In addition, prominent degeneration of the anterolateral funiculus and severe loss of neurons in the intermediate zone of the spinal cord were evident, without marked alteration of the corticospinal tracts. Degeneration of the subthalamic nucleus, increased iron deposition in the substantia nigra, and axonal swelling, residual nodules and acidophilic granules in the spinal ganglia were found. The patient's condition was considered to have been a forme fruste or incipient form of widespread-type amyotrophic lateral sclerosis (ALS) or motor neuron disease (MND) with pallido-nigro-luysian atrophy (PNLA). The neuropathological features of the present case appear to be important for understanding the nature of widespread-type ALS and MND with PNLA.