Myonecrosis and myofibrosis as complications of sickle cell anemia.

Painful crises in sickle cell anemia are associated with infarction and subsequent fibrosis of many different organs. Myonecrosis secondary to muscle infarction during a crisis and subsequent fibrosis are often not recognized as complications of sickle cell anemia. We describe four patients, all of whom had recurrent episodes of symmetric proximal muscle pain and swelling as prominent features of their crises. Muscle biopsies showed acute myonecrosis with a minimal inflammatory reaction as well as myofibrosis with abundant collagen deposition. Chronic sequelae consisted of muscle induration, atrophy, and contractures.