A 55-year-old man presented with four-year history of progressive muscle wasting and
weakness. His medical history disclosed advanced stage silicosis. The examination
revealed flaccid quadriparesis with proximal amyotrophy. Serum creatine-kinase levels
and screening for metabolic and inflammatory disorders were unremarkable. Muscle biopsy
showed myopathic findings and the presence of abnormal amorphous and heterogeneous
intracytoplasmic and subsarcolemmal content ([Figure]).
Figure Chest CT-scan and muscle biopsy findings in silicosis. (A, B) Axial chest CT-scan
showing bilateral severe advanced stage interstitial lung disease with marked lung
architectural distortion (black arrow). Deltoid muscle biopsy showing abnormal subsarcolemmal
and intracytoplasmic content disclosed in red in trichrome Gomori stain (C-E; white
arrow) and black in NADH-TR histochemistry (F-H; white arrow-head).
Toxic myopathies can result from environmental and occupational exposure to toxic
agents[1]. Silicosis results from the deposition of crystalline silicon dioxide (silica) in
lung and is associated with different systemic involvement, including osteoporosis,
susceptibility to autoimmune disorders, constrictive pericarditis[2] and, rarely, myopathy.
