A paraneoplastic syndrome (PNS) is a set of symptoms and signs that can accompany the formation of a cancer but is not due to its direct infiltration or metastasis. PNS results from the secretion of peptides or hormones by tumor cells or from an immunological cross-reaction between the tumor antigens and host antigens. In the adult population, PNS affects up to 15% of patients with cancer, but data on pediatric patients remain lacking. The remarkable fact is that PNS can precede an oncology diagnosis, even by months or years. PNS can involve virtually any organ of the human body. In children, the most commonly involved are the nervous system (encephalitis, opsoclonus-myoclonus syndrome), skin (pemphigus, alopecia areata, pruritic skin, pyoderma gangrenosum, skin nevi), rheumatologic (dermatomyositis, vasculitis), liver (atrophic biliary syndrome, idiopathic cholestasis), endocrine system (hypercalcemia, syndrome of inadequate secretion of antidiuretic hormone), kidney (nephrotic syndrome), or hematopoietic system (hemolytic anemia, thrombocytopenia, eosinophilia, thrombotic macroangiopathy, leukomoid reaction). PNS can accompany all childhood cancers, but is most common in Hodgkin lymphoma, acute lymphoblastic and myeloid leukemia, neuroblastoma, Wilms tumor, and sarcoma. Diagnosis of PNS should begin as early as the suspicion of its unusual course, lack of response to standard treatment, or prolonged duration. Diagnosis should include typical disease-specific tests and simultaneous imaging of the head and neck, abdomen, and pelvis, as well as a bone marrow biopsy to look for malignancy. PNS treatment mainly includes anti-tumor therapy and sometimes additional immunosuppressive therapy. This article aims to review PNS in children with malignancy.

Background: Hyperleukocytosis, defined as a total leukocyte count of more than 50,000/mm³ leukocytes, occurs in almost one in five children with acute lymphoblastic leukemia (ALL). It represents an unfavorable prognostic factor in this disease. The aim of the following study was to describe demographic and clinical features in patients with hyperleukocytosis and their relationship with leukocyte count. Methods: We retrospectively analyzed the available medical data of patients with ALL diagnosed and treated at the University Children’s Hospital in Lublin between 2017 and 2024. Results: Of the 97 patients, 10 (10.3%) had hyperleukocytosis. They were significantly more likely to be older boys diagnosed with T-ALL. The group with hyperleukocytosis had a higher mortality rate. The presence of hyperleukocytosis also correlated with the presence of petechiae, thrombocyte and neutrophil counts, and LDH activity. Patients with hyperleukocytosis also experienced a higher incidence of infections as a complication of therapy as leukocyte counts increased. Conclusions: Hyperleukocytosis, although rare, is an important factor in the course of ALL, both clinically and prognostically.

Acute lymphoblastic leukemia is the most common type of childhood cancer, accounting for about 23% of all cancers diagnosed in this age group. The last stage of radical treatment is remission maintenance, during which hospitalization is not necessary. The lesions occurring in the oral cavity...

Background/Objectives: Acute lymphoblastic leukemia (ALL) is the most common childhood cancer, accounting for 80% of leukemias in this group and about 25% of all cancers. The 5-year survival rate is now over 90%. Achieving such a good outcome is made possible by the introduction of intensive, high-dose chemotherapy. However, it is associated with numerous complications, affecting up to 80% of patients. Among the most common of these are infections and intestinal, hepatic, hematological or neurological complications. For their effective treatment and prevention, it is necessary to develop predictors. High hopes in this aspect are placed on miRNAs. The aim of the following paper is to present the role of miRNAs as predictors of chemotherapy complications in children with ALL. Methods: A systematic review of the available literature in the PubMed, Scopus, Embase and Google Scholar scientific databases was conducted. Fourteen publications were included in the analysis. Results: Changes in miRNA expression and single-nucleotide polymorphisms in miRNAs are associated with complications of ALL therapy. Among the most notable are miR-1206 (in mucositis and myelotoxicity), miR-2053 (in neurotoxicity and mucositis), miR-938 and miR-3117 (in gastrointestinal toxicity and neurotoxicity), miR-1307 (in gastrointestinal toxicity and mucositis) and miR-323b (in gastrointestinal toxicity and myelotoxicity). In addition, miR-155, miR-3117 and miR-4268 may be potential therapeutic targets in complications of ALL therapy. Conclusions: miRNAs are good potential predictors of ALL chemotherapy toxicity and may be therapeutic targets in these complications.

The treatment of acute lymphoblastic leukemia (ALL) in children has become increasingly effective over the years. Currently, the cure rate is about 90%. This has become possible due to the use of combinations of appropriate chemotherapeutics in very high, often maximum doses. This is associated...