Capillary alterations and mononuclear cell infiltrate in a case of diabetic amyotrophy

A 56 year-old man with diabetes mellitus and pain, muscle weakness and wasting in both thighs, of three months duration, had a diagnosis of diabetic amyotrophy. The ultrastructural study of a biopsy from quadriceps femoris muscle showed usual findings in muscle fibers and two not previously reported alterations: capillary necrosis and mononuclear cell infiltration consisting of macrophages, lymphocytes and plasma cells. The etiopathogenesis of muscle damage in diabetic amyotrophy is discussed.