Radiological Findings and Genetic Rearrangements in Paediatric Patients with Acute Lymphoblastic Leukaemia.

Objective: To evaluate differences in radiological phenotypes between B-cell acute lymphoblastic leukemia (B-ALL) and T-cell acute lymphoblastic leukemia (T-ALL) in pediatric patients and to assess their correlation with specific genetic alterations.

Study design: A single-center retrospective cohort study was conducted including 144 pediatric patients (n = 115 B-ALL, n = 29 T-ALL) diagnosed with acute lymphoblastic leukemia. Comprehensive clinical, laboratory, and multi-modal imaging data (X-ray, computed tomography, magnetic resonance imaging, and ultrasonography) were analyzed. Radiological findings were correlated with molecular profiles, including KMT2A, ETV6::RUNX1, BCR::ABL1, IKZF1, and CDKN2A/B alterations. Principal outcomes included the prevalence of specific imaging features across leukemia subtypes and their association with genetic abnormalities. Statistical significance was assessed using appropriate comparative analyses.

Results: T-ALL demonstrated a more aggressive, mass-forming phenotype, with significantly higher rates of superior mediastinal widening 41.67% (n = 10) and mediastinal masses on CT 38.1% (n = 8) compared with B-ALL 12.28% (n = 14) and 2.56% (n = 2), respectively; p < 0.01. In contrast, B-ALL more frequently presented with diffuse interstitial pulmonary opacities 42.31% (n = 33). T-ALL was also associated with greater systemic and central nervous system involvement, including a higher prevalence of ischemic lesions on MRI 62.5% (n = 5) vs 24.0% (n = 12) and inguinal lymphadenopathy 37.5% (n = 3). Molecular analysis showed that KMT2A rearrangements and IKZF1 deletions were associated with disseminated disease, including pulmonary nodules and multi-organ infiltration. In B-ALL, CDKN2A/B deletions 31.3% (n = 36) were linked to hepatomegaly and inflammatory sinus changes.

Conclusion: Distinct radiological patterns differentiate the space-occupying phenotype of T-ALL from the more heterogeneous presentation of B-ALL. The observed imaging-genetic associations are promising and hypothesis-generating. Although significant results have been obtained, it is necessary to conduct prospective multicenter cohorts. A multimodal diagnostic approach is essential for accurate disease characterization and individualized management in pediatric ALL.