Indications and Limitations of Sirolimus in the Treatment of Vascular Anomalies-Insights From a Retrospective Case Series.

Background: Despite recent developments, the role of sirolimus in the heterogeneous spectrum of vascular anomalies is yet to be defined, in terms of indication, dosage, and therapy duration, recognizing both its potential and limitations. Methods: We retrospectively analyzed 16 children with vascular anomalies treated with sirolimus in two pediatric centers between 2014 and 2020 [male: n = 7, the median age at diagnosis: 4.6 months (range, 0-281.4)]. In addition, repetitive volumetric analyses of the vascular anomalies were performed when possible (11 cases). Results: Ten patients were diagnosed with vascular malformations and 6 with vascular tumors. The mean therapy duration was 27.2 months (range, 3.5-65). The mean sirolimus level was 8.52 ng/ml (range, 5.38-12.88). All patients except one with central conducting lymphatic anomaly responded to sirolimus, with the most noticeable volume reduction in the first 4-6 months. Additional administration of vincristine was needed in five patients with kaposiform hemangioendothelioma and yielded a response, even in cases, refractory to sirolimus monotherapy. As a single agent, sirolimus led to impressive improvement in a patient with another vascular tumor-advanced epithelioid hemangioendothelioma. Complicated vascular malformations required long-term sirolimus therapy. Side effects of sirolimus included mucositis and laboratory abnormalities. No major infectious episodes were recorded. An infant with COVID-19, diagnosed while on sirolimus therapy, presented with a mild course. Conclusion: In the current series, we reported limitations of sirolimus as monotherapy, addressing the need to redefine its indications, and explore combination regimens and multimodal treatment strategies. Tools for objective evaluation of response trends over time could serve as a basis for the establishment of future therapeutic algorithms.

Interdisciplinary Radical "En-Bloc" Resection of Ewing Sarcoma of the Chest Wall and Simultaneous Chest Wall Repair Achieves Excellent Long-Term Survival in Children and Adolescents.

Introduction: Ewing sarcomas of the chest wall, historically known as "Askin tumors" represent highly aggressive pediatric malignancies with a reported 5-year survival ranging only between 40 and 60% in most studies. Multimodal oncological treatment according to specific Ewing sarcoma protocols and radical "en-bloc" resection with simultaneous chest wall repair are key factors for long-term survival. However, the surgical complexity depends on tumor location and volume and potential infiltrations into lung, pericardium, diaphragm, esophagus, spine and major vessels. Thus, the question arises, which surgical specialties should join their comprehensive skills when approaching a child with Ewing sarcoma of the chest wall. Patients and Methods: All pediatric patients with Ewing sarcomas of the chest wall treated between 1990 and 2020 were analyzed focusing on complete resection, chest wall reconstruction, surgical complications according to Clavien-Dindo (CD) and survival. Patients received neo-adjuvant chemotherapy according to the respective Ewing sarcoma protocols. Depending on tumor location and organ infiltration, a multi-disciplinary surgical team was orchestrated to perform radical en-bloc resection and simultaneous chest wall repair. Results: Thirteen consecutive patients (seven boys and six girls) were included. Median age at presentation was 10.9 years (range 2.2-21 years). Neo-adjuvant chemotherapy (n = 13) and irradiation (n = 3) achieved significant reduction of the median tumor volume (305.6 vs. 44 ml, p < 0.05). En-bloc resection and simultaneous chest wall reconstruction was achieved without major complications despite multi-organ involvement. Postoperatively, one patient with infiltration of the costovertebral joint and laminectomy required surgical re-intervention (CD IIIb). 11/13 patients were treated with clear resections margins (R1 resection in one patient with infiltration of the costovertebral joint and marginal resection <1 mm in one child with multiple pulmonary metastases). All patients underwent postoperative chemotherapy; irradiation was performed in four children. Two deaths occurred 18 months and 7.5 years after diagnosis, respectively. Median follow-up for the remaining patients was 8.8 years (range: 0.9-30.7 years). The 5-year survival rate was 89% and the overall survival 85%. Conclusion: EWING specific oncological treatment and multi-disciplinary surgery performing radical en-bloc resections and simultaneous chest wall repair contribute to an improved survival of children with Ewing sarcoma of the chest wall.

Novel phenotypes observed in patients with ETV6-linked leukaemia/familial thrombocytopenia syndrome and a biallelic ARID5B risk allele as leukaemogenic cofactor.

Background. The phenotypes of patients with the recently discovered, dominant, ETV6-linked leukaemia predisposition and familial thrombocytopenia syndrome are variable, and the exact mechanism of leukaemogenesis remains unclear. Patients and Methods. Here, we present novel clinical and laboratory phenotypes of seven individuals from three families with ETV6 germline mutations and a refined genetic analysis of one child with additional high-hyperdiploid acute lymphoblastic leukaemia (HD-ALL), aiming to elucidate second oncogenic hits. Results. Four individuals from two pedigrees harboured one novel or one previously described variant in the central domain of ETV6 (c.592C>T, p.Gln198* or c.641C>T, p.Pro241Leu, respectively). Neutropenia was an accompanying feature in one of these families that also harboured a variant in RUNX1 (c.1098_1103dup, p.Ile366_Gly367dup), while in the other, an autism-spectrum disorder was observed. In the third family, the index patient suffered from HD-ALL and life-threatening pulmonary mucor mycosis, and had a positive family history of 'immune' thrombocytopenia. Genetic analyses revealed a novel heterozygous mutation in the ETS domain of ETV6 (c.1136T>C, p.Leu379Pro) along with absence of heterozygosity of chromosome (10)(q21.2q21.3), yielding a biallelic leukaemia risk allele in ARID5B (rs7090445-C). The neutrophil function was normal in all individuals tested, and the platelet immune histochemistry of all three pedigrees showed delta-storage-pool defect-like features and cytoskeletal defects. Conclusions. Our clinical observations and results of high-resolution genetic analyses extend the spectrum of possible phenotypes cosegregating with ETV6 germline mutations. Further, we propose ARID5B as potential leukaemogenic cofactor in patients with ETV6-linked leukaemia predisposition and familial thrombocytopenia syndrome.

Enterovirus infections in pediatric hematologic/oncologic patients.

BACKGROUND: Enteroviruses (EV) are a large group of Picornaviruses associated with respiratory, gastrointestinal, and neurologic symptoms in the immunocompetent host. Little is known about the epidemiologic and clinical impact in pediatric hematologic/oncologic patients. PROCEDURE: From 2001 through 2017, different clinical specimens were collected from pediatric hematologic/oncologic patients and were tested for enteroviral RNA. RESULTS: Of 13 004 specimens collected from 761 patients, 38 (0.3%) obtained from 14 patients (1.8%) tested positive for EV RNA. Viral shedding was observed without viremia and vice versa. None of 80 cerebrospinal fluid specimens obtained from 60 patients with neurologic symptoms were positive for EV RNA. None of 14 patients positive for EV RNA showed EV-specific symptoms. In 11/14 patients, EV RNA was found to be negative in the follow-up specimen. The remaining patient with a severe primary immune deficiency showed repeated positive EV RNA results for >5 years. CONCLUSIONS: In this pediatric hematologic/oncologic cohort, EV infection occurred rarely and without related symptoms. Specimens concurrently obtained from one patient are commonly not in accordance with each other. In the vast majority of patients, EV RNA appears to turn negative in the follow-up specimen. EV infections seem to have a low impact in this patient cohort.

The Phenotype and Treatment of WIP Deficiency: Literature Synopsis and Review of a Patient With Pre-transplant Serial Donor Lymphocyte Infusions to Eliminate CMV.

Early diagnosis of primary immunodeficiency disorders (PID) is vital and allows directed treatment, especially in syndromes with severe or profound combined immunodeficiency. In PID patients with perinatal CMV or other opportunistic, invasive infections (e.g., Pneumocystis or Aspergillus), multi-organ morbidity may already arise within the first months of life, before hematopoietic stem cell transplantation (HSCT) or gene therapy can be undertaken, compromising the definitive treatment and outcome. Deficiency of Wiskott-Aldrich syndrome (WAS) protein-interacting protein (WIP deficiency) causes an autosomal recessive, WAS-like syndrome with early-onset combined immunodeficiency that has been described in three pedigrees to date. While WAS typically includes combined immunodeficiency, microthrombocytopenia, and eczema, the clinical and laboratory phenotypes of WIP-deficient patients-including lymphocyte subsets, platelets, lymphocyte proliferation in vitro, and IgE-varied widely and did not entirely recapitulate WAS, impeding early diagnosis in the reported patients. To elucidate the phenotype of WIP deficiency, we provide a comprehensive synopsis of clinical and laboratory features of all hitherto-described patients (n = 6) and WIP negative mice. Furthermore, we summarize the treatment modalities and outcomes of these patients and review in detail the course of one of them who was successfully treated with serial, unconditioned, maternal, HLA-identical donor lymphocyte infusions (DLI) against life-threatening, invasive CMV infection, followed by a TCRαß/CD19-depleted, treosulfan/melphalan-conditioned, peripheral blood HSCT and repetitive, secondary-prophylactic, CMV-specific DLI with 1-year post-HSCT follow-up. This strategy could be useful in other patients with substantial premorbidity, considered "too bad to transplant," who have an HLA-identical family donor, to eliminate infections and bridge until definitive treatment.

Malignancy and chemotherapy induced haemophagocytic lymphohistiocytosis in children and adolescents-a single centre experience of 20 years.

Haemophagocytic lymphohistiocytosis (HLH) is a possibly life-threatening syndrome of immune dysregulation and can be divided into primary (hereditary) and secondary forms (including malignancy-associated HLH (M-HLH)). We retrospectively analysed epidemiological, clinical, virological and laboratory data from patients with M-HLH treated at our department between 1995 and 2014. Out of 1.706 haemato-/oncologic patients treated at our department between 1995 and 2014, we identified 22 (1.29%) patients with secondary HLH (1.3-18.0, median 10.1 years; malignancy induced n = 2; chemotherapy induced n = 20). Patients with acute myeloblastic leukaemia (AML) developed HLH significantly more often than patients with acute lymphoblastic leukaemia (ALL) (10/55, 18.2% vs. 6/148, 4.1%, p = 0.0021). As possible viral triggers, we detected BKV (53.8% of the tested patients), HHV-6 (33.3%), EBV (27.8%), CMV (23.5%), ADV (16.7%) and PVB19 (16.7%) significantly more frequently than in haemato-/oncologic patients without HLH. Despite lacking evidence of concurrent bacterial infection, C-reactive protein (CRP) and procalcitotnin (PCT) were elevated in 94.7 and 77.7% of the patients, respectively. Ferritin and sIL2R were markedly elevated in all patients. HLH-associated mortality significantly (p = 0.0276) decreased from 66.6% (1995-2004) to 6.25% (2005-2014), suggesting improved diagnostic and therapeutic management. Awareness of HLH is important, and fever refractory to antibiotics should prompt to consider this diagnosis. Elevated ferritin and sIL2R seem to be good markers, while inflammatory markers like CRP and PCT are not useful to discriminate viral triggered HLH from severe bacterial infection. Re-/activation of several viruses may play a role as possible trigger.

Immune Thrombocytopenia in Two Unrelated Fanconi Anemia Patients - A Mere Coincidence?

Thrombocytopenia and pancytopenia, occurring in patients with Fanconi anemia (FA), are interpreted either as progression to bone marrow failure or as developing myelodysplasia. On the other hand, immune thrombocytopenia (ITP) represents an acquired and often self-limiting benign hematologic disorder, associated with peripheral, immune-mediated, platelet destruction requiring different management modalities than those used in congenital bone marrow failure syndromes, including FA. Here, we describe the clinical course of two independent FA patients with atypical - namely immune - thrombocytopenia. While in one patient belonging to complementation group FA-A, the ITP started at 17 months of age and showed a chronically persisting course with severe purpura, responding well to intravenous immunoglobulins (IVIG) and later also danazol, a synthetic androgen, the other patient (of complementation group FA-D2) had a self-limiting course that resolved after one administration of IVIG. No cytogenetic aberrations or bone marrow abnormalities other than FA-typical mild dysplasia were detected. Our data show that acute and chronic ITP may occur in FA patients and impose individual diagnostic and therapeutic challenges in this rare congenital bone marrow failure/tumor predisposition syndrome. The management and a potential context of immune pathogenesis with the underlying marrow disorder are discussed.

Sirolimus for the treatment of children with various complicated vascular anomalies.

Vascular anomalies include a heterogeneous group of disorders that are categorized as vascular tumors or vascular malformations. Treatment options include resection, embolization, laser therapy, and sclerotherapy or medical treatment such as propranolol, steroids, interferon, and cytostatic chemotherapy. Mammalian target of rapamycin seems to play a key role in the signal pathway of angiogenesis and subsequently in the development of vascular anomalies. Recently, the successful use of sirolimus has been reported in children with lymphatic malformations and kaposiform hemangioendotheliomas. We report on six patients with different vascular anomalies (kaposiform hemangioendothelioma n = 2, combined lymphatico-venous malformation n = 2, pulmonary lymphangiectasia n = 1, and orbital lymphatic malformation n = 1) who were treated with peroral sirolimus. Three of the children initially presented with a Kasabach-Merrit phenomenon. Median duration of treatment was 10 months; two children are still on treatment. Three children each achieved complete and partial remission. Kasabach-Merrit phenomenon resolved within 1 month in all patients. Treatment with sirolimus was tolerated well; only mild reversible leukopenia was observed. CONCLUSION: Sirolimus proved to be effective in children with complicated lymphatic or lymphatico-venous malformations and kaposiform hemangioendotheliomas. Treatment was tolerated well with acceptable side effects. The optimum length of treatment and possible long-term side effects have to be evaluated. WHAT IS KNOWN: • Vascular anomalies including vascular tumors and vascular malformations may lead to life-threatening conditions.• Some patients are refractory to established treatment and/or are not available for local invasive procedures. WHAT IS NEW: • We reviewed the literature focusing treatment of vascular anomalies inc hildren and adolescents.• Our data support recent studies that sirolimus is an effective treatment option in patients with complicated vascular tumors andmalformations

Dynamics of Graft Function Measured by DNA-Technology in a Patient with Severe Aplastic Anemia and Repeated Stem Cell Transplantation.

Although bone marrow transplantation (BMT) from an HLA identical sibling is considered as treatment of choice in pediatric patients with severe aplastic anemia (SAA), a significant number of them experience graft failure (GF) after BMT. We report a case of an 8-year-old male patient with SAA who presented with a complicated posttransplant course due to parvovirus B19 infection and GF. A subsequent attempt to support the graft by antithymocyte globulin (ATG) and a peripheral stem cell boost resulted in transitory autologous recovery of hematopoiesis followed by mixed chimerism, supported by donor lymphocyte infusions (DLIs) and finally graft rejection with relapse of SAA. Permanent complete chimerism was achieved by a second BMT. Dynamics of graft function, measured by a single nucleotide polymorphism (SNPs) analysis, are discussed.