Sporadic Late-Onset Nemaline Rod Myopathy: An Interesting Case.

Area of Science:

• Neurology
• Muscle Pathology
• Rare Diseases

Background:

• Sporadic late-onset nemaline rod myopathy is a rare acquired adult-onset neuromuscular disorder.
• It is characterized by proximal muscle weakness and the presence of nemaline rods within muscle fibers.
• Unlike the congenital form, adult-onset prevalence is notably infrequent.

Observation:

• A 60-year-old male presented with gradually worsening proximal muscle weakness.
• Electromyography revealed a myopathic pattern.
• Muscle biopsy showed type 1 and 2 muscle fiber atrophy, minimal inflammation, and granular deposits on modified Gomori trichrome staining.

Findings:

• Ultrastructural examination confirmed the presence of numerous nemaline rods in myofibers.
• These findings led to the diagnosis of sporadic late-onset nemaline myopathy.
• The case highlights the diagnostic challenges and the importance of recognizing this rare myopathy.

Implications:

• Awareness of sporadic late-onset nemaline myopathy is essential for clinicians.
• Timely and accurate diagnosis can prevent treatment failure and improve patient prognosis.
• Potential associations with monoclonal proteins warrant consideration in adult patients.