Morphologic aspects of fibromyalgia

The most common morphological finding in muscle biopsis in longstanding fib romyalgia is type II fiber atrophy. This can be found in many other conditi ons such as disuse atrophy, affections of the corticospinal tracts, steroid atrophy, and other different neuromuscular disorders. An increase in lipid droplets and a slight proliferation of mitochondria in type I muscle fiber s are correlated with the duration of fibromyalgia. In some cases we could find some ragged red fibers (RRF) which histochemically show a pronounced a ccumulation of lipids and mitochondria and single fiber defects of cytochro me-c-oxidase. In some fibromyalgia patients with RRF, we could find deletio ns of the mitochondrial genoma.