Myasthenia gravis: clinical and histological features in relation to thymectomy

SYNOPSIS The clinical and thymic histological features of 23 patients who underwent thymectomy for myasthenia gravis have been examined and compared. Eighty-two per cent of patients with a non-neoplastic gland containing numerous germinal centres improved postoperatively, whereas 83 % of patients with a non-neoplastic gland containing no germinal centres deteriorated or died. Glands with only slight involution and containing numerous germinal centres were more commonly seen in young female patients. The evidence relating thymic histological appearances with the postoperative progress of patients with myasthenia gravis is reviewed. An association between myasthenia gravis and the thymus gland was first suggested by Weigert in 1901. Although Schumacher and Roth (1913) reported the clinical improvement of a patient with myasthenia after removal of an enlarged non-neoplastic gland, it was not until the reports of Blalock et al. (1939) and Keynes (1949) that the beneficial effect of thymectomy was fully appreciated. Keynes concluded that, although the connection between myasthenia and abnor-malities of the thymus gland was well estab-lished, there was no clue to how or why the gland acquired its abnormal function. Only recently have the histological appear-ances of the thymus gland and their relation to the clinical progress of patients after thymec-tomy received greater attention (Castleman an