Thymectomy: the More You Know, the More You Know You Don't Know.

During the first decade of the 20th century, long before John Simpson proposed that myasthenia gravis might be an autoimmune disorder, Oppenheim and Weigert identified tumours of the thymus in patients with myasthenia, leading to the theory that myasthenia might be an endocrine disorder. In 1911, Ernst Sauerbruch partially removed the thymus of a young myasthenic woman in the treatment of hyperthyroidism and was surprised to find that her myasthenia improved. This resulted in a variety of treatments directed against the thymus for myasthenia with varying results. In 1939, Alfred Blalock removed a thymic tumour using the new technique of tracheal intubation and sternotomy, and in 1941, he performed the first trans-sternal thymectomy on a patient with myasthenia, but without a thymic tumour. By 1944, he had performed 20 such thymectomies with improvement in 13 patients. However, in 1947 he concluded, “I thought we had an answer to this problem of the relationship to the thymus and myasthenia, but such does not appear to be the case.” Subsequent case series described varying techniques and outcomes, possibly accounted for by later evidence that successful thymectomy requires removal of microscopic islands of …