The thyroid glands were studied morphologically in 32 patients with myasthenia gravis on whom autopsies had been performed. In six instances (approximately 19% of cases), changes suggestive of thyroiditis were observed, while in a large control group the incidence of such thyroid changes was 0.9%. The finding suggests that a basic relationship may exist between these conditions.
Becker KL, Titus JL, McConahey WM, Woolner LB. Morphologic Evidence of Thyroiditis in Myasthenia Gravis. JAMA. 1964;187(13):994-996. doi:10.1001/jama.1964.03060260022004