A case of anti-HMGCR myopathy in a patient with breast cancer and anti-Th/To antibodies.

Statins competitively inhibit the activity of HMGCR (3-hydroxy-3-methylglutaryl coenzyme A reductase), which is a key enzyme in cholesterol synthesis. These are effective drugs for the management of cardiovascular disease and are generally well tolerated but several side effects have been reported. Muscular adverse symptoms are various and, rarely, statin exposure may lead to authentic immune-mediated necrotizing myopathy (IMNM), namely anti-HMGCR myopathy.