Invasive Fungal Infections in Pediatric Hematology-Oncology: A 12-Year Single-center Observational Study and the Need for a Clinical Classification System

Pediatric patients undergoing chemotherapy or allogeneic hematopoietic stem cell transplantation are at high risk for invasive fungal infections (IFIs). Diagnosing IFIs is challenging due to nonspecific clinical presentations, invasiveness of diagnostic procedures, and the low sensitivity of microbiological assays. This retrospective 12-year observational study examines incidence, diagnostic challenges, fungal pathogens, and course of IFI cases in pediatric patients with hematologic malignancies or receiving allogeneic hematopoietic stem cell transplantation at the University Children's Hospital of Basel. Of the 163 patients reviewed, 39 (23.9%) received antifungal therapy based on clinical suspicion of IFI. Applying the EORTC/MSGERC diagnostic classification system, only 19 cases (11.6% cumulative incidence) were confirmed as proven or probable IFIs. Within this subgroup, a mortality rate of 21% underscores the severe consequences associated with advanced disease and profound immunosuppression. In addition, we introduce a novel clinical classification system to complement the EORTC/MSGERC criteria, with the aim of enhancing early diagnosis and risk stratification in this high-risk population. Our findings highlight the diagnostic challenges in pediatric patients, including the low specificity of radiologic findings and the limited utility of microbiological tests in guiding treatment decisions. Addressing these gaps is crucial for improving outcomes and advancing care for children with IFIs.