AIM:To assess the clinical-biological characteristics and outcomes of Croatian pediatric patients with acute lymphoblastic leukemia (ALL). A secondary aim was to evaluate the predictive value of pretreatment leukemia-associated immunophenotypes (LAIPs) for poor early response to induction therapy defined as ≥10% day 15 bone marrow flow cytometry minimal residual disease (FCM-MRD). METHODS:This retrospective cohort study reviewed the medical data of 393 consecutive pediatric ALL patients diagnosed and treated from February 2003 to April 2017 at four Croatian pediatric hemato-oncology centers. FCM data of 379 non-infant patients enrolled in two consecutive intercontinental trials, ALL IC-BFM 2002 (NCT00764907) and ALL IC-BFM 2009 (EudraCT 2010-019722-13), were analyzed to evaluate the association between LAIPs at diagnosis and day 15 FCM-MRD≥10% using univariate and multivariate logistic regression. RESULTS:The median age at diagnosis was 5.2 years, with a predominance (83%) of B-cell precursor (BCP) ALL, and high hyperdiploidy (25.1%) and ETV6::RUNX1 (18.7%) as the most common genetic abnormalities. The protocols did not significantly differ in 5-year event-free survival (82.1% vs 81.7%), overall survival (88% vs 85%), and cumulative incidence of relapse (12.3% vs 10%). FCM-MRD≥10% on day 15 was identified in 22.1% of patients and was predicted by white blood cell (WBC) count ≥20×109/L (P=0.011) and strong expression of CD34 (P=0.032) and CD13 (P=0.001) at diagnosis. CONCLUSION:The characteristics and survival rates of Croatian pediatric ALL patients aligned with ALL IC-BFM data. WBC≥20×109/L, CD34strong, and CD13strong independently predicted poor early response in BCP-ALL, suggesting a potential prognostic value of LAIPs at diagnosis.

Acquired coagulopathy is a rare, potentially life-threatening disorder which should be suspected if acute bleeding in patients with a negative previous hemorrhagic diathesis is encountered. This disease arises due to the formation of antibodies against clotting factors in a previously healthy child or adult, which specifically partially or completely neutralize the procoagulant activity of clotting factors or accelerate their removal from the circulating blood, reducing their plasma concentrations and increasing the bleeding tendency. The aforementioned disorder should be confirmed by determining global coagulation times, concentrations of individual clotting factors, and determining the presence of specific or non-specific antibodies. Timely treatment aimed at prompt stopping of bleeding and eradicating the resulting inhibitors will prevent the unfavorable outcome. It is recommended to continue monitoring patients in the outpatient setting with determination of PT and APTT for a year, because in 20% of cases a relapse of the disease occurs, although more often in adults. In this paper, we presented a three-year-old boy in whom we determined prolonged global coagulation times and the presence of non-specific inhibitors of the coagulation factors F II, F IX, F XI and F XII through the diagnostic workup of macrohematuria. The treatment with fresh frozen plasma and corticosteroids resulted in clinical improvement and disease remission. Acquired coagulopathy is a very rare disorder in childhood with scarce literature data. The aim of this paper is to demonstrate the possible causes, clinical course and treatment of this life-threatening disorder in children.

Acute leukemias are the most common malignant diseases in childhood. The aims of this retrospective cohort study were to investigate the frequency of cytogenetic abnormalities in acute pediatric leukemia; the correlation between cytogenetic abnormalities and 5-year survival; and the correlation between cytogenetic abnormalities and clinical and laboratory features. We included 105 patients; acute lymphoblastic leukemia (ALL) had 80.9% patients, B-cell lineage ALL (B-ALL) 84.7% of them, and T-cell lineage (T-ALL) 15.3%. The overall 5-year survival for B-ALL was 85.9% and for T-ALL was 84.6%. The most common cytogenetic abnormalities in patients with B-ALL were t(12;21)(p13.2;q22.1); ETV6-RUNX1 with 22.2% and hyperdiploidy with 19.4%. Our survival analysis showed that t(12;21)(p13.2;q22.1); ETV6-RUNX1 and t(1;19)(q23;p13.3); TCF3-PBX1 had the best 5-year survival with 100% of patients surviving, whereas t(v;11q23.3); KMT2A rearranged had the worst 5-year survival of just 33.3% of patients surviving after 5 years. We found no difference in 5-year survival in B-ALL when comparing clinical features. Acute myelogenous leukemia had 20 patients with 70.6% 5-year survival. The most common cytogenetic abnormality in acute myelogenous leukemia was t(8;21)(q21;q22.1); RUNX1-RUNX1T1 (20%). In conclusion, this study showed the correlation of different cytogenetic abnormalities with 5-year survival in B-ALL patients. Such correlation was not found when comparing clinical features and 5-year survival of patients with B-ALL. This emphasized the significance of cytogenetic analysis in pediatric leukemia.

Germ cell tumors (GCTs) are a heterogeneous group of neoplasms that arise from the primordial germ cells of the human embryo, which are normally destined to produce reproductive cells sperm, or ova. GCTs can be present in both gonadal GCTs and extragonadal GCT sites. Pediatric GCTs are relatively rare tumors with an incidence of 2%-3%. Primary mediastinal germ cell tumors GCTs are very rare extragonadal GCTs that arise in the anterior mediastinum. In this report, we present the case of a 16-year-old boy with primary seminoma arising in the anterior mediastinum. The patient presented with the symptoms of cough, fever, and chest tightness. CT finding was in favor of a large expansive process measuring 12.4x6.7x14.2 cm in the anterior mediastinum, accompanied by a conglomeration of hilar lymph nodes in the level of brachiocephalic veins juncture. Fine needle biopsy and core biopsy were performed transthoracically, under the control of MSCT. Based on histology and immunohistochemistry, the diagnosis of mediastinal germ cell tumor with immunophenotype of seminoma was made. The patient was treated with 4 cycles of chemotherapy by BEP protocol without significant side effects and toxicities. The patient remained disease-free for 16 months. The purpose of reporting this case is to confirm that chemotherapy with cisplatin-based regimens has markedly improved the outcome of adults and children with GCTs as well.

L-asparaginase has been an essential component of paediatric-based multiagent therapy for children diagnosed with haematological cancer. Drug’s effect is based on depletion of asparagine in the circulatory system thus depriving unmatured malignant cells of amino acid. However, some children are faced with silent inactivation or, in worst cases, an allergic reaction to the drug and is recommended to monitor drug activity levels in order to detect these patients and modify the therapy. We had set up the first laboratory for asparaginase-activity testing in Croatia at the Department of Laboratory diagnostics, Children’s Hospital Zagreb. Our aim is to present the first experiences in asparaginase monitoring from March 2018 till October 2020 from the 2 pediatric centers (Zagreb and Split). Children between 1 and 18 years old with diagnosed pediatric acute lymphoblastic leukemia (ALL) or lymphoma (NHL) were included in the prospective L-asparaginase study. Blood samples were collected prior to and during treatment. Serum was separated and frozen prior to shipping. Over 100 samples were processed, among which some were repeatedly measured in order to determine the inter-day precision due to sample thawing. Activities of three commercially available drugs, E. coli-derived asparaginase or Erwinia chrysanthemi asparaginase or E.coli pegylated, PEG-asparaginase were measured in intervals as recommended. Laboratory measurements used plate reader-based indooxine method where L-aspartic beta-hydroxamate (AHA) was a substrate for the enzyme. The reading time was optimized to ensure the best results. 41 patients (38 ALL and 3 lymphoma cases) were included in the study. Among thirty native E. coli asparaginase–treated patients, three (10%) of them developed an allergy and four (13%) of them showed silent inactivation. Patients without hypersensitivity to native drug had serum median trough levels of 281,3 U/L after 48 h. Six patients were treated with Erwinia asparaginase; one developed an allergy and none silent inactivation while others had median through levels 90,3 U/L after 48 h. The PEG asparaginase therapy was given to 4 patients where median trough decline was observed (938,4 U/L, 479,5 U/L, 170,3 U/L for 7, 14 or 21 days, respectively). Serum samples were stabile after second thawing as were no significant difference in asparaginase level after re-testing. Additionally, the absorbance results showed no significant difference between the 10 minutes reading intervals. Here we conclude that therapeutic drug monitoring is important for pediatric patients with hematological cancer. The spectrophotometric-based method showed precise performance and has been added to our routine clinical protocols.

Acute lymphoblastic leukemia (ALL) is a malignant disease of lymphoid precursors. According to immunophenotype, it is further subdivided into precursor B cell ALL and precursor T cell ALL, with precursor B cell ALL being much more common both in children and adults. Lineage switch from one lymphoid lineage to another during the course of the disease is extremely rarely reported. Here, we describe a case of a child who initially presented as a precursor B-ALL but 15 years later and after two successfully treated relapses of the original ALL presented with early T cell precursor leukemia. Although it was considered as a relapse, it could be interpreted as a case of secondary leukemia, which can be explained as a consequence of treatment as well as a constitutional feature of an individual. Also, it draws attention to the possibility that hematopoietic cells, and in that context also leukemic cells, are much more plastic and capable of reprogramming than previously thought.

Objectives – Vitamin D (VD) has an impact on the immune system via vitamin D nuclear receptor (VDR) present in various types of immune cells. Its anti-angiogenic, pro-apoptotic, and anti-proliferative effect have been found as well. We investigated VD status of paediatric patients with malignant disease such as leukaemia, lymphoma, Langerhans cell histiocytosis, and solid malignant tumours. Materials and Methods – In children with malignant disease from the case cohort, total 41, serum VD level was measured upon first admission to the hospital. They were subdivided into those with leukaemia / lymphoma and those with solid malignant tumours (body and central nervous system). Langerhans cell histiocytosis was included in leukaemia /lymphoma group. The optimal level for VD was recommended to be >75 nmol/L. The insufficiency was presented with levels of 25-OH VD between 50 and 75 nmol/L, while levels ≤50 nmol/L were recognized as deficiency. We further categorized deficiency as strong (30 – 49.9 nmol/L), significant (20 – 29.9 nmol/L) and extreme (<20 nmol/L). Results – Only three patients had optimal level of VD. All others (92.8%) suffered from VD insufficiency 11 (26.8%) and various levels of deficiency: 10 (24.4%) from strong, 11 (26.8%) significant, and 6 (14.6%) from extreme. Conclusions – The prevalence of VD insufficiency/deficiency in paediatric patients with malignant disease is very high especially in patients with solid malignant tumour. Such condition, regarding that VD insufficiency/deficiency can debilitate immune system may have a negative impact on these patients.

Autoimuna hemolitička anemija (AIHA) je bolest uzrokovana nastankom protutijela usmjerenih protiv antigena na površini vlastitiheritrocita. Ovisno o termalnim obilježjima, autoprotutijela se dijele na: hemolitičke anemije uzrokovane “toplim” i “hladnim” protutijelima. AIHA-i mogu biti primarni i sekundarni. Sekundarni AIHA-i su udruženi s nekom drugom bolešću poput sistemskog lupusaeritematodesa, imunodefi cijencije ili limfoproliferativog poremećaja. Osnovno obilježje AIHA-a je pozitivan direktni Coombsov testkoji otkriva protutijela klase IgG i dijelove komplementa (najčešće anti- C3) vezane na površinu eritrocita. Evansov sindrom je istodobna ili uzastopna pojava AIHA-a s pozitivnim direktnim Coombsovim testom i imune trombocitopenije (ITP). U radu smo prika zalidvogodišnjeg dječaka u kojeg je u dobi od 10 mjeseci dijagnosticiran AIHA rekurentnog tijeka. U dobi od 17 mjeseci uz osnovnu bolest otkriven je i ITP te je postavljena dijagnoza Evansovog sindroma. Dječak je liječen glukokortikoidima, pripravkom humanihimunoglobulina, transfuzijama deplazmatiziranih eritrocita i koncentratom trombocita u više navrata, ali bez remisije bolesti. Naposljetku, primjenom rituksimaba postignuto je kliničko poboljšanje i višemjesečna remisija bolesti.

Anaplastic large-cell lymphoma is a rare disease in children, and endobronchial localization is extremely rare in any age group. We report the case of a 13-year-old girl with endobronchial anaplastic lymphoma kinase-positive anaplastic large-cell lymphoma presenting as asthma, and discuss the diagnostic, therapeutic, and clinical implications.

In the past ten years great success has been accomplished in the diagnostics and treatment of hematological and oncological diseases in children. New methods in diagnostics and treatment ("home" therapy, prophylaxis,immunosupresive therapy, bone marrow transplantation, new combinations of cytostatics, irradiation, surgery and monoclonal antibody) have made it possible to accomplish a high percentage of long term remission and cures in these patients. The paper presents current possibilities of diagnostics and treatment and results achieved in children with hematological and oncological diseases in the world and in the Republic of Croatia.

Extrarenal occurrence of Wilms' tumor is exceptional and the diagnosis is almost always made after surgery. The exact mechanism whereby a Wilms' tumor occurs in extrarenal tissue is unknown. The tumor is most commonly located in the retroperitoneum or inguinal region. Localization in subcutaneous tissue is extremely rare. In this paper, the case of a 1-month-old female infant with an extrarenal Wilms' tumor located in the lumbosacral region is presented. Surgical excision is the treatment of choice, and the same general therapeutic rules should be followed as when the kidney is affected.

Maligne bolesti su jedan od vodecih uzroka smrti djece u Europi i Sjedinjenim Americkim Državama. Posljednjih desetak godina postignut je bitan napredak, kako u dijagnostici tako i njihovom lijecenju. Uvođenjem novih metoda lijecenja (nove kombinacije citostatika, zracenja, kirurskog zahvata, monoklonskih antitijela te transplantacije kostane srži) i u ovih je bolesnika danas moguce postici visoki postotak dugotrajnih remisija i izljecenja.

Impairment of respiratory function is one of the most sensitive indicators used in the evaluation of the effects of air pollution on human health. We compared predicted values of flow-volume curve according to Knudson and the spirometry results in 81 healthy children; 40 girls and 41 boy, aged (10.69 +/- 2.24) years. We also measured the transfer factor of the lungs for carbon monoxide (TLCO) using the single-breath method and compared the results with reference values by Cotes. Patients were selected randomly among pre-school and elementary school children from the Split area, who were residentially exposed to asbestos. Children with atopic diseases, family history of atopy, history of severe respiratory diseases, and history of smoking were excluded from study. We found a statistically significant difference in FVC (p < 0.0001) from normal values according to Knudson, but when expressed in the percentage of the Knudson values, this difference was not significant (p > 0.05). No statistically significant difference was found for FEV1, FEF75, FEF50, FEF25, and FEV1/FVC. TLCO reached (107.37 +/- 20.50)% of normal values according to Cotes, and was not significantly different. At this point, it is hard to predict the consequences of exposure to low levels of asbestos in childhood, because it takes a long time for complications such as neoplasms, pulmonary fibrosis, or respiratory insufficiency to develop.

Haemophilia is a genetic haemorrhagic disorder characterised by the absence of VIII or IX coagulation factors and is treated with supplemental factors VIII or IX. Haemophilia A is the most common and accounts for 70% of all inherited coagulopathies. At the Paediatric Department, KBC Split from January, 1(st) 2003 to February 15 2008 28 haemophiliacs were registered. 21 with haemophilia A (75%), and 7 with haemophilia B (25%), 8 (38%) patients had mild haemophilia A. 6 (29%) moderate, and 7 (33%) severe. Two children (29%) had moderate haemophilia B, and 5 (71%) severe. 12 (42%) patients received monthly prophylaxis. 6 with severe haemophilia A (67%), and 3 (33%) with severe haemophilia B. Children were treated in the outpatients' clinic for 649 days, on average 6 days, most often because of an ankle, elbow, and knee injury or epistaxis. Children were hospitalized 17 times. 79% with haemophilia A, and 21% with haemophilia B, mostly because of head, frontal thoracic and joint injuries. Hospitalisation lasted on average 8 days. Inhibitors were not registered, while two children developed mild haemophilic arthropathy.