Pathology of skeletal muscle in fibromyalgia: a histo-immuno-chemical and ultrastructural study.

The value of muscle biopsy in fibromyalgia is still questioned. In this study we obtained 50 quadriceps biopsies from 20 patients and compared them blindly to 10 biopsies from five normal controls. Using light microscopy, histochemical and immunoenzymatic methods we found no definite evidence of muscle disease. Nevertheless, we subjected biopsies from nine of the patients and five other controls for further ultrastructural evaluations and demonstrated pathologic findings e.g. empty sleeves of basement membrane, many lipofuschin bodies and other degenerative changes. We conclude that ultrastructural evaluation cannot yet be used for diagnostic purposes, but the negative findings with light microscopy, including histochemical and immunoenzymatic techniques, might be of importance in evaluating difficult cases.