< p > < /p > Keywords: acute myeloid leukemia hyperleukocytosis leukostasis

Fibroblastic tumors are a heterogeneous group of soft tissue neoplasms. The treatment of these tumors has always been challenging, given their rarity and heterogeneity. The management was based on surgical excision, and chemotherapy was added in advanced metastatic disease. The rapid development of molecular and genetic diagnostics allowed further understanding of the complexity of fibroblastic tumors and the use of targeted therapies, especially kinase inhibitors (KI). Thanks to them, crippling procedures can be omitted, and the subsequent successful treatment lines are possible. However, many questions are still related to KI and its place in treatment protocols. Researchers debate whether KI can replace chemotherapy in the first line of treatment. The need for recommendations switches the decision to physicians and parents. In this paper, we focus on the benefits and problems of KI in fibrosarcoma treatment in the pediatric population. Keywords: fibrosarcoma NRTK inhibitors infantile fibrosarcoma targeted treatment

Serratia species are Gram-negative pathogens responsible for a wide range of nosocomial infections. This multicenter nationwide retrospective study aimed to describe the epidemiology, clinical characteristics, antimicrobial susceptibility, and outcomes of Serratia infections in pediatric oncology patients and hematopoietic stem cell transplantation (HSCT) recipients in Poland between 2012 and 2023. A total of 36 Serratia infection episodes were identified in patients under 20 years of age, including 30 cases (83.3%) in the oncological (OHD) group and six (16.7%) among HSCT recipients. The median age was 4.30 years. The most common underlying diseases were acute lymphoblastic leukemia (36.1%) and central nervous system tumors (16.7%). Bloodstream infections predominated in OHD patients (33.3%), whereas urinary tract infections were most frequent in HSCT recipients (83.3%). S. marcescens was the most commonly isolated species. More than half of isolates (53.3%) showed antimicrobial resistance, with extended-spectrum β-lactamase (ESBL)-producing strains in 26.7% and AmpC β-lactamase-producing strains in 13.3%. Multidrug resistance occurred in 30%. Treatment most often included amikacin, piperacillin/tazobactam, and carbapenems. Five deaths occurred in the OHD group and one in the HSCT group, none directly related to Serratia infection. Although uncommon, Serratia infections remain clinically relevant due to their high antimicrobial resistance, underscoring the need for antimicrobial stewardship.