A case of neuromuscular mimicry

Area of Science:

• Neurology
• Pathology
• Immunology

Background:

• Amyotrophic lateral sclerosis (ALS) presents with progressive motor neuron degeneration.
• Mimicking ALS symptoms can complicate differential diagnosis, necessitating comprehensive investigations.

Observation:

• A patient presented with symptoms suggestive of probable ALS, including dysarthria, dysphagia, tongue fasciculations, and hyperreflexia.
• Electromyography (EMG) was inconclusive, prompting a muscle biopsy.
• The biopsy revealed widespread nemaline rods, initially suggesting sporadic late-onset nemaline myopathy.

Findings:

• Post-mortem examination identified nemaline bodies in all muscles examined.
• The autopsy also revealed an unexpected diagnosis of sarcoid brainstem encephalitis.
• This indicates that nemaline rods can be a feature of neurosarcoidosis.

Implications:

• Neurosarcoidosis should be considered in the differential diagnosis of patients presenting with ALS-mimic syndromes.
• The presence of nemaline rods in various disorders is expanded to include neurosarcoidosis.
• This case highlights the importance of thorough post-mortem examination for definitive diagnosis in complex neurological presentations.