Immunologic studies of a case of myasthenia gravis associated with pemphigus vulgaris after thymomectomy.

A case of myasthenia gravis was associated with thymoma and pemphigus vulgaris. The bullous lesions developed after partial thymomectomy, cobalt (60Co) irradiation, and 3 days' extensive sunbathing, although a retrospective study of the patient's sera by quantitative indirect immunofluorescence method indicated that antiepithelial antibody already was positive before the clinical appearance of pemphigus vulgaris. Serial observation of the patient's clinical course and titrations of antiepithelial, antimuscle, and antithymus antibodies suggested a reverse relationship between the severity of myasthenia gravis and titers of antimuscle and anitithymus antibodies, and a parallel relationship between pemphigus vulgaris and antiepithelial antibody. Review of the literature suggests a close relationship between pemphigus vulgaris and myasthenia gravis and thymoma, particularly thymoma injured by medical procedures.