The role of skin and muscle biopsy in the diagnosis of main connective tissue diseases.

Systemic involvement in autoimmune diseases is often unclear and organ changes are confounding, thus making it difficult to have an early accurate diagnosis. In those situations, both clinical and paraclinical findings might orientate the diagnosis, but only histological or immunohistochemistry changes might be accurate enough. The skin histological changes are relevant and sometimes might have a tremendous role in the accurate diagnosis of autoimmune rheumatic diseases, due to the correlation with the clinical systemic manifestations of the diseases and through the accessibility of biopsy. In the same time, muscle biopsy can provide important support for physicians improving diagnosis and optimizing management of connective tissue diseases.