Hemorrhagic Cystitis Following Hematopoietic Stem Cell Transplantation in Children: A Single Pediatric Center Experience

Background Hemorrhagic cystitis (HC) is a frequent and potentially severe complication following hematopoietic stem cell transplantation (HSCT) in children. It significantly affects the quality of life and prolongs hospitalization. Despite its frequency, no standardized management guidelines exist. This study aimed to describe the characteristics, risk factors, and treatments of HC in a pediatric HSCT population. Methods We conducted a retrospective single‐center study including all pediatric patients who underwent allogeneic HSCT between January 2007 and December 2022. HC was defined and graded according to the European Conference on Infections in Leukaemia (ECIL) guidelines. We analyzed risk factors, BK virus (BKV) viruria, treatments, and outcomes. Results HC occurred in 24 patients (14.7%), with a median onset at 27.5 days post‐HSCT. Acute graft‐versus‐host disease (aGVHD) was significantly associated with HC occurrence (45.8% vs. 19.4%, p = 0.01), particularly in its severe forms ( p = 0.007). BKV was detected in 66.7% of HC cases. Viral load in urine was not significantly associated with HC severity or duration. All patients received supportive care; cidofovir was used in 79.2%, with increasing frequency in higher grade HC. Severe cases required multimodal management, including intravesical installations, hyperbaric oxygen therapy (HBO; 37.5%), and arterial embolization (all Grade 4 cases). No deaths were directly attributed to HC. Conclusions HC remains a significant and morbid complication after pediatric HSCT. Our findings highlight the need for early identification of high‐risk patients and access to timely, multidisciplinary interventions. Multicenter prospective studies are essential to standardize care and improve outcomes in this vulnerable population.