Optimizing Diagnosis and Surgery for Pure Anterior Mediastinal Cysts: Insights from a Single-Centre Study

Pure anterior mediastinal cysts (pAMC) are uncommon and typically benign lesions. In contrast to solid anterior mediastinal tumours, there are no standardized diagnostic or management guidelines, despite a small but clinically significant risk of malignancy. The goal of this study was to identify preoperative factors associated with malignancy in order to develop a clinical algorithm to guide the diagnosis and management of pAMC.

This retrospective single-centre study was conducted at Toulouse University Hospital and included patients diagnosed with pAMC between January 2012 and June 2025. Logistic regression was used to identify preoperative predictors of thymoma or germ cell tumours.

A total of 70 patients were diagnosed with pAMC, 26 of whom underwent surgical resection. On multivariate analysis, hypermetabolism on positron emission tomography-computed tomography (PET-CT) was significantly associated with a final pathological diagnosis of thymoma or germ cell tumour (odds ratio, 43.21 [2.81-663.93], P = .007). Lesion size greater than 4 cm was also associated with malignancy on univariate analysis (odds ratio: 10.50 [1.50-73.67], P = .02), though this did not remain significant in multivariate analysis. Based on these findings, we proposed a decision-making algorithm incorporating PET-CT as a first-line investigation.

Hypermetabolism on PET-CT is a strong preoperative predictor of malignancy in lesions presenting as pAMC. Prospective multicentre studies are warranted to validate additional prognostic markers and optimize imaging strategies for the management of pAMC.