An Autopsy Case of Amyotrophic Lateral Sclerosis With Sudden Death Showed Histological Features of Lewy Body Disease

We present the case of an 81-year-old man diagnosed with probable amyotrophic lateral sclerosis (ALS) based on the Updated Awaji criteria. The patient exhibited progressive motor neuron degeneration with muscle weakness, atrophy, and fasciculations primarily in the right lower limb and later extending to the right upper limb. Three months after being referred to a home care clinic, he collapsed in front of his family members and died. An autopsy revealed phosphorylated TDP-43 pathology consistent with ALS, with involvement of the hypoglossal nucleus, facial nerve nucleus, and medulla oblongata. Interestingly, widespread a-synuclein pathology indicative of diffuse neocortical type Lewy body disease (LBD; Braak stage 6) was identified, despite the absence of clinical parkinsonism or dementia with Lewy bodies (DLB) during his lifetime. The presence of autonomic symptoms such as constipation and urinary retention shortly before death may be attributable to a-synuclein pathology affecting the autonomic nervous system. The coexistence of ALS and LBD underscores the clinical challenge of diagnosing overlapping pathologies, as motor symptoms may obscure signs of LBD. Dopamine transporter imaging or MIBG myocardial scintigraphy might aid in identifying preclinical LBD in ALS patients with atypical symptoms. The patient died of respiratory failure due to extensive organizing pneumonia, but the possibility of sudden cardiac arrest could not be excluded. This case highlights the potential for coexisting neurodegenerative pathologies in ALS, emphasizing the importance of comprehensive evaluation when autonomic symptoms or other atypical features are present.