Anti-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase (anti-HMGCR) myopathy is a subtype of immune-mediated necrotizing myopathy regardless of exposure to statins. Necrotizing myopathy is distinguished by necrotic muscle fibers with a relative lack of inflammation. It is frequently associated with a high risk of permanent muscle damage and disability. Recent studies have suggested a slightly increased risk of cancer in patients with anti-HMGCR myopathy. This report describes a case of statin-naïve paraneoplastic anti-HMGCR myopathy, with rapidly progressive muscle weakness leading to respiratory failure.

Anti-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase (anti-HMGCR) myopathy is a subtype of immune-mediated necrotizing myopathy regardless of exposure to statins. Necrotizing myopathy is distinguished by necrotic muscle fibers with a relative lack of inflammation. It is frequently associated with a high risk of permanent muscle damage and disability. Recent studies have suggested a slightly increased risk of cancer in patients with anti-HMGCR myopathy. This report describes a case of statin-naïve paraneoplastic anti-HMGCR myopathy, with rapidly progressive muscle weakness leading to respiratory failure.