22q11.2 deletion syndrome (22q11.2DS) is one of the most common congenital malformation syndromes resulting from disrupted embryonic development of pharyngeal pouches. The classical triad of symptoms described by Angelo DiGeorge is frequently accompanied by hematological and immune disorders. While it is well-established that patients with 22q11.2DS have an increased risk of recurrent autoimmune cytopenias, including immune thrombocytopenia, the platelet abnormalities in this population are more complex and multifaceted. Given this issue, we conducted a comprehensive literature review on platelet disorders in 22q11.2DS using accessible databases (PubMed and Scopus). We aimed to outline previous studies limitations and most urgent challenges concerning thrombocytopenia in these patients. One characteristic finding frequently observed in 22q11.2DS is mild macrothrombocytopenia caused presumably by the loss of one GP1BB allele, encoding the element of the GPIb–IX–V complex. This structure plays a central role in thrombocyte adhesion, aggregation, and subsequent activation. Recent studies suggest that defective megakaryopoiesis and impaired vasculogenesis may strongly influence platelet and hemostasis disorders in 22q11.2DS. Furthermore, the phenotypic manifestation may be modulated by epigenetic factors and gene expression modifiers located outside the deletion region. Although the final hemorrhagic phenotype is typically mild, these patients may require more frequent transfusions following major surgical procedures. Despite the risk of thrombocytopenia and thrombocytopathy, there is a lack of large-scale research on hematological anomalies in 22q11.2DS, and the available results are often inconclusive. Given the complexity of hemostatic disorders, it is essential to establish specific recommendations for perioperative management and autoimmune cytopenias treatment within this population.

B‐cell precursor acute lymphoblastic leukemia (BCP‐ALL) with the t(5;14)(q31;q32) chromosomal translocation resulting in an IGH::IL3 fusion is an exceptionally rare lymphoid malignancy presenting with hypereosinophilia. Germline PAX5 alterations, including sequence variants and deletions, are associated with a selective susceptibility to BCP‐ALL and lymphomas, based on a limited number of affected families worldwide. Here, we report a 6‐year‐old male with BCP‐ALL with the t(5;14)(q31;q32) translocation and harboring a novel constitutional PAX5 variant (NM_016734.3:c.[295dup];[=], p.[(Ile99Asnfs*3)];[(=)]). Despite the low representation of the leukemic clone in the bone marrow, the IGH::IL3 fusion was identified by both fluorescent in situ hybridization (FISH) and optical genome mapping (OGM). Although hypereosinophilia poses a risk of multiorgan damage, our patient exhibited only pneumonia and asymptomatic neuroimaging alterations in the central nervous system. The patient achieved remission by the end of induction and is currently continuing maintenance therapy. In line with existing literature, familial segregation of the PAX5 variant demonstrated high but incomplete penetrance, as two leukemia‐free mutation carriers displayed only subclinical B lymphocyte maturation abnormalities without hypogammaglobulinemia. Our report underscores the diagnostic utility of OGM, which unequivocally demonstrated the characteristic translocation. Typically, BCP‐ALL in affected family members exhibits secondary somatic aberrations involving the wild‐type PAX5 allele, including structural variants or loss of heterozygosity (LOH) of chromosome 9p, as well as PAX5 somatic mutations. To our knowledge, this is the first human report aligning with animal models, which suggests that secondary alterations activating the JAK–STAT pathway may potentially contribute to leukemogenesis in a PAX5 mutation background.

Inherited thrombocytopenias (ITs) constitute a heterogeneous group of congenital bleeding disorders caused by defects in over 50 genes that predominantly affect platelet production. GFI1B has recently emerged as a critical transcriptional regulator of megakaryocyte and erythroid differentiation. Its dysfunction underlies a rare autosomal dominant form of IT, which usually results in moderately reduced platelet counts. We report an adult male with lifelong severe thrombocytopenia (platelet count range 10–20 × 10⁹/L) and recurrent bleeding episodes since early childhood. Comprehensive molecular analysis identified a heterozygous NM_001377304.1:c.814 + 1G > A variant in the zinc finger region of GFI1B, resulting in a frameshift and premature truncation. The proband exhibited hallmark features of this IT subtype, including α‑granule deficiency and persistent CD34 expression in megakaryocytes and platelets. Based on preclinical evidence, the patient initially received eltrombopag, followed later by romiplostim, achieving a partial platelet response and improvement in bleeding symptoms. Familial analysis revealed marked variability in platelet counts and bleeding phenotypes among carriers of the same variant, including the patient’s mother, highlighting that clinical outcomes cannot be reliably predicted from genotype alone. A literature review confirmed considerable phenotypic heterogeneity in GFI1B-related thrombocytopenia, indicating that variant type and location only partially account for disease severity. This report represents the first in-human use of thrombopoietin receptor agonists in GFI1B-related thrombocytopenia. It underscores the challenges in diagnosing and managing ITs and emphasizes the importance of early genetic testing. Further studies are needed to elucidate the molecular determinants of phenotypic variability and to develop targeted therapeutic strategies for affected patients.

Thrombopoietin receptor agonists (TPO-RAs) have become an important component of pediatric immune thrombocytopenia (ITP) management, with growing evidence supporting their use in other hematologic disorders. We conducted a retrospective single-center study evaluating TPO-RA use at a pediatric oncohematology center in Poland between 1 January 2016, and 31 March 2026. Clinical indications, treatment patterns, efficacy, and safety outcomes were analyzed. Treatment response was defined as initial response (IR, platelet count [PLT] > 50 × 10⁹/L), complete response (CR, PLT > 100 × 10⁹/L), and sustained response (SR, PLT > 50 × 10⁹/L maintained in ≥75% of visits over 6 months). Thirty-five patients were included in the analysis. The most common indication was ITP (27/35, 77%), followed by severe aplastic anemia (5/35, 14%), poor graft function (2/35, 6%), and inherited platelet disorders (1/35, 3%). TPO-RA use increased over time, with more than half of patients (20/35, 57%) initiating therapy between 2024 and 2026. Overall IR, CR, and SR rates were 77%, 63%, and 61%, respectively, with a median time to response of 7 days (interquartile range [IQR], 7–12.5). TPO-RAs were increasingly used earlier in the disease course, including in rescue and off-label settings. Treatment was well tolerated, with only grade 1–2 adverse events reported. Our real-world data confirm the high efficacy and favorable safety profile of TPO-RAs in pediatric patients and support their expanding role in pediatric hematology beyond disease-specific indications.

Neuroblastoma constitutes the most frequent solid tumor in children under 2 years of age. It is most often located in the abdomen; however, it may also be found in the mediastinum or the neck, and its first and only symptom may be Horner syndrome (HS). Because various imaging and laboratory examinations may be employed in order to detect the tumor, the objective of our study was to assess their sensitivity in detecting neuroblastoma in children with HS. The study comprised data from 14 oncologic departments in Poland and involved children with a clinical diagnosis of neuroblastoma. In total, 729 patients were included in the analysis who were diagnosed between 2004 and 2022. HS occurred before the neuroblastoma diagnosis in 3.29% of cases. The study evaluated the sensitivity of lactate dehydrogenase (LDH), ferritin and neuron-specific enolase (NSE) serum concentration, dopamine and vanillylmandelic acid urinary levels, as well as of chest radiography in the detection of neuroblastoma tumor. The combination of urinary catecholamines demonstrated a low sensitivity (72.57%). However, chest radiography proved to be highly effective in identifying lesions associated with neuroblastoma (92.31% sensitivity in patients with HS on the first presentation), which may be further enhanced by means of performing LDH, ferritin, and NSE blood concentration tests (100% sensitivity). Our findings indicate that chest radiography and serum laboratory tests may represent valuable tools in the primary diagnosis of HS etiology. In contrast, urinary catecholamines test should not be considered a diagnostic criterion.