A retrospective clinical analysis of pediatric mediastinal space-occupying lesions in a Chinese children's hospital from 2015 to 2024.

Background: Pediatric mediastinal space-occupying lesions (MSOLs) encompass a wide spectrum of conditions, including benign and malignant, infectious and reactive, as well as congenital and acquired. The differential diagnosis of pediatric MSOLs remains a clinical challenge. This single-center study aimed to analyze relevant clinical features of MSOLs and to improve the accuracy of their differential diagnosis. Methods: A retrospective analysis was conducted of MSOLs diagnosed over a 10-year period. Information on etiology, demographic characteristics, lesion localization, clinical manifestations, and diagnostic approach was collected. Results: We reviewed 461 cases of pediatric MSOLs from a single institution. The most common type was lymphoma, followed by neurogenic tumors, congenital diaphragmatic hernia, foregut duplication cysts, and infectious diseases. Etiology varied significantly across age groups. Hiatus hernia was the most common lesion in infants (0-12 months), while lymphoblastic lymphoma predominated in children (12-180 months). Lesion distribution also differed among mediastinal compartments: T-lymphoblastic lymphoma was most frequent in the prevascular compartment, hiatus hernia in the visceral compartment, and neuroblastoma in the paravertebral compartment. Forty patients (8.7%) were asymptomatic. Among symptomatic patients, common presentations included cough, chest tightness, fever, nausea/vomiting, chest pain, and facial or neck edema. Malignancies were predominantly found in the prevascular and paravertebral compartments with chest symptoms, whereas non-neoplastic lesions mainly involved the visceral compartment and presented with gastrointestinal symptoms or asymptomatic. Diagnostic approaches included non-invasive imaging and biopsy. Definitive diagnoses were established by imaging alone in 139 cases (30.2%); the remaining patients underwent image-guided or surgical biopsies. Conclusion: This study reveals a diverse, age-dependent spectrum of pediatric MSOLs. Accurate diagnosis relies on a combination of clinical presentation, compartment-specific localization, and a multidisciplinary approach utilizing both advanced imaging and image-guided or surgical biopsies, which were demonstrated to be safe and effective. These findings can aid significantly in the differential diagnosis and management of pediatric MSOLs.