Correlations between inflammatory biomarkers and clinicopathological features in surgically resected thymic epithelial tumors: implications for preoperative diagnosis

Objective This study aimed to analyze the correlations between pathological characteristics, risk factors, and inflammatory biomarkers in patients with thymic epithelial tumors (TETs) undergoing surgical resection. Methods A retrospective cohort of adult patients with histopathologically confirmed TETs undergoing radical resection between 2015 and 2024 was analyzed. The Kruskal–Wallis test was employed to evaluate associations of systemic immune-inflammation index (SII), platelet-to-lymphocyte ratio (PLR), and neutrophil-to-lymphocyte ratio (NLR) with clinical features (age; gender; myasthenia gravis (MG); World Health Organization (WHO) stage; tumor size; Masaoka stage; WHOMScore). A nomogram diagnostic model was constructed to differentiate thymoma from thymic carcinoma. Results A total of 111 patients (52 males, 59 females) were enrolled, including eight cases of type A thymoma, 38 type AB, nine type B1, 16 type B2, 12 type B3, and 28 thymic carcinomas. Correlations between SII, NLR, PLR, and clinicopathological features (gender, age, MG, tumor size, risk stratification, Masaoka stage, and WHO classification) were analyzed. Significant differences in SII, NLR, and PLR were observed across WHO classifications ( P SII < 0.001; P NLR < 0.001; P PLR = 0.004). Dunn’s test further revealed that these differences primarily stemmed from distinctions between thymoma and thymic carcinoma groups. Based on PLR and MG status, a combined diagnostic model was developed, which demonstrated favorable performance in differentiating thymoma from thymic carcinoma (AUC = 0.804). Conclusion Our findings suggest that inflammatory biomarkers (SII, NLR, and PLR) are significantly associated with the malignancy of TETs. The combination of PLR and MG status may serve as a useful auxiliary tool for distinguishing thymoma from thymic carcinoma, showing potential for clinical application.