[The muscular lesion in myasthenia gravis: study of 17 cases with muscular histochemistry].

A study of 17 muscle biopsies from patients with myasthenia gravis was done, using freshfrozen section and histochemistry tecnics. It was found 15 abnormal muscle biopsies. The most common abnormality were small dark angular fibers, excess of lipids droplets outside the muscle membrane, changes in fiber size and type II fiber atrophy. These findings suggested denervation in 11 biopsies, type II fiber atrophy in 7, linfocyte infiltration in 4, fiber necrosis with fagocitosis in 1 and 2 were normal. Was noted a direct correlation between the disease duration and the severity of the histological abnormality. Two patients had tymoma. Congenital myasthenia gravis, rheumatoid arthritis, intersticial hypertrophic neuritis, Hashimoto tireoiditis and concomitance of myasthenic syndrome was found once in different patients.