Autoimmune diseases and malignancies in patients with thymoma: A 9-year retrospective study

To the Editor: Thymoma, a rare thymic epithelial tumor (1.3–3.2 per million individuals per year),[1] is classified by WHO-2021 into types A, AB, B, micronodular thymoma with lymphoid stroma (MNT-LS), metaplastic, and lipofibroadenoma. Thymoma is found to be associated with autoimmune diseases (ADs) and other malignancies.[2] Nevertheless, previous studies lack a systematic investigation of factors associated with ADs in patients with thymoma, as well as an exploration of the connections between ADs and other malignancies or different pathological classifications; therefore, we conducted this retrospective study. We retrieved the list of patients diagnosed with thymoma from the Department of Pathology at West China Hospital, Sichuan University, from January 1, 2016, to December 31, 2024. Patients with duplicate records and with incomplete clinical information were excluded. Thymoma was diagnosed and classified according to the 2021 WHO classification criteria after pathological biopsy. This study has obtained ethical approval from West China Hospital’s Ethics Committee (No. 2025(434)) and informed consent was waived. Medical records were reviewed to extract patients’ clinical information. Univariate and multivariate logistic regression analyses were conducted to identify potential factors associated with ADs. We included all variables (age, gender, Masaoka–Koga stage, presence of other malignancies, the temporal sequence of diagnosis between thymoma and other tumors or ADs, pathological classification, follow-up duration, and comorbidities) in a univariate logistic regression model. Variables with significant differences (P