2024 Volume 67 Issue 7 Pages 268-274
The patient was an 81-year-old woman diagnosed with thymoma at 66 years old. The thymoma was surgically removed but recurred repeatedly during follow-up, and surgery was performed at 71 and 79 years old. She had no history of glucose intolerance, but thirst and weight loss appeared at the end of January X-1. In April of the same year, she was started on intensive insulin therapy after showing blood glucose 320 mg/dL, HbA1c 12.2 %, and urinary ketone body 3+. She was diagnosed with acute-onset type 1 diabetes mellitus because of deficient insulin secretion. Although islet-associated autoantibodies were negative, the diagnosis of chronic thyroiditis and presence of disease-sensitive HLA led us to suspect that this patient had autoimmune type 1 diabetes caused by thymoma-induced autoreactive T cell production and an impaired regulatory T cell maturation and function. To our knowledge, there are only four antibody-negative cases of thymoma-associated type 1 diabetes mellitus, and we report this case because it is considered an interesting and rare case in considering the pathogenesis of type 1 diabetes mellitus.
