Abstract
Introduction: Autoimmune polyglandular syndrome (APS) is characterized by the association of autoimmune, endocrine and non-endocrine organ-specific diseases, and is classified into four types depending on the affected organs. APS type III is defined as an association between autoimmune thyroid disease and other autoimmune diseases such as gastrointestinal, neuromuscular, skin, and other diseases. Case report: This report describes the clinical case of a 22-year-old male patient with Graves' Disease, Vitiligo and Myasthenia Gravis diagnosed by well-established clinical criteria and complementary tests such as autoimmunity markers and imaging tests. complications presented by the patient, the treatment instituted and its clinical evolution. Discussion: The case described is compared with the findings reported in the literature, addressing the epidemiology, clinical presentation, diagnostic methods and available treatments, emphasizing the importance of detailed clinical investigation, in order to make earlier diagnoses and treat patients adequately.