Non-anaplastic peripheral T cell lymphoma in children and adolescents-an international review of 143 cases

Hematopoietic stem cell transplantation for pediatric patients with non-anaplastic peripheral T-cell lymphoma. An EBMT pediatric diseases working party study

Peripheral T-cell lymphomas (PTCL) other than anaplastic large-cell lymphoma are rare in children, and the role of hematopoietic stem cell transplantation (HSCT) has not been clarified yet. In a retrospective analysis of registry-data of the European Society for Blood and Marrow Transplantation we analyzed 55 patients aged < 18 years who received allogeneic (N = 46) or autologous (N = 9) HSCT for PTCL. Median age at HSCT was 13.9 years; 33 patients (60%) were in first remission, and 6 (19%) in progression at HSCT. Conditioning was myeloablative in 87% of the allogeneic HSCTs and in 27 (58.7%) based on total body irradiation. After allogeneic HSCT the 5-year overall- and progression-free survival was 58.9% (95% CI 42.7-71.9) and 52.6% (95% CI 36.8-66.1), respectively. 5-year relapse incidence was 27.6% (95% CI 15.1-41.6), the non-relapse mortality rate was 19.8% (95% CI 9.7-32.6). Five of the six patients with progression at HSCT died. Seven of nine patients after autologous HSCT were alive and disease-free at last follow-up. Our data suggest a role of allogeneic HSCT in consolidation-treatment of patients with high-risk disease, who reach at least partial remission after primary- or relapse-therapy, whereas patients with therapy-refractory or progressive disease prior to transplantation do not profit from HSCT.

"Sandwich" protocol based on modified SMILE regimen for children with newly extranodal NK/T cell lymphoma, nasal type: a single-arm, single-center clinical study

Extranodal NK/T-cell lymphoma, nasal type (ENKTL), which is a rare form of mature T/NK cell lymphoma in children, currently lacks a standardized first-line treatment approach. However, a treatment protocol known as the "sandwich" regimen has been used in children newly diagnosed with ENKTL. This protocol combines the administration of methotrexate, ifosfamide, etoposide, pegaspargase, and dexamethasone (referred to as SMILE) with the addition of radiotherapy (RT). From September 2017 to December 2020, a total of five patients were included in the study, consisting of three males and two females. The median age of onset was 10.6 years (range, 9.8 to 14.0 years). Among the patients, four had nasal/nasopharyngeal disease at stage II, while one patient had extra nasal disease involving the skin at stage IV. The median EBV-DNA level in plasma was 1.68 × 103 copies/ml (range, 0.44 to 21.1 × 103copies/ml). All the patients had good overall response after 2 cycles of chemotherapy and radiotherapy, including 4 of the patients who had a complete response and 1 of the patients with partial remission. The patient with stage IV received allogeneic hematopoietic stem cell transplantation after the EBV-DNA level was elevated again during treatment. One patient in the low-risk group experienced grade 4 oral mucositis, while no other severe complications or treatment-related deaths were observed. The median follow-up period was 22 months (range, 5 to 57 months). All five patients successfully completed their treatment, with four patients achieving event-free survival, and one patient was lost to follow-up. The median OS time and EFS time was 33 months (range: 18-57 months) and 20 months (range: 5-47 months), respectively. The sandwich protocol has demonstrated a high response rate, good tolerance to chemotherapy, and no treatment-related fatalities. However, further confirmation is necessary through additional clinical studies involving larger sample sizes. Clinical trial registration number: Due to modified SMILE regimens with sandwiched radiotherapy yielded promising outcomes in children ENKTL, we have carried out a phase II multicenter clinical trial (ChiCTR220005954) for children ENKTL in China to further verify the efficacy and safety.

Children's Oncology Group's 2023 blueprint for research: Non-Hodgkin lymphoma

Pediatric non-Hodgkin lymphoma (NHL) includes over 30 histologies (many with subtypes), with approximately 800 cases per year in the United States. Improvements in survival in NHL over the past 5 decades align with the overall success of the cooperative trial model with dramatic improvements in outcomes. As an example, survival for advanced Burkitt lymphoma is now >95%. Major remaining challenges include survival for relapsed and refractory disease and long-term morbidity in NHL survivors. Langerhans cell histiocytosis (LCH) was added to the NHL Committee portfolio in recognition of LCH as a neoplastic disorder and the tremendous unmet need for improved outcomes. The goal of the Children' Oncology Group NHL Committee is to identify optimal cures for every child and young adult with NHL (and LCH). Further advances will require creative solutions, including engineering study groups to combine rare populations, biology-based eligibility, alternative endpoints, facilitating international collaborations, and coordinated correlative biology.

Spontaneous remission of angioimmunoblastic T-cell lymphoma in a child with ataxia-telangiectasia: a case report

BACKGROUND

Angioimmunoblastic T-cell lymphoma is an uncommon subtype of peripheral T-cell lymphoma in children with fewer than 20 cases reported in literature.

CASE PRESENTATION

A 3-year-old Omani boy was diagnosed with ataxia-talengectasia presenting with fever and generalized lymphadenopathy. His biopsy revealed atypical lymphocytic infiltrate consistent with the diagnosis of angioimmunoblastic T-cell lymphoma. Within 3 weeks from the initial presentation and without any neoadjuvant therapy, he showed complete recovery of symptoms with absence of fever and regression of all previously affected lymph nodes. He has remained in remission ever since.

CONCLUSION

This is the first report of spontaneous improvement of angioimmunoblastic T-cell lymphoma in a patient with ataxia-telangiectasia who was 3 years old at presentation. Owing to the paucity of similar cases, this report adds valuable diagnostic, therapeutic, and monitoring data.

Pediatric Autologous Hematopoietic Stem Cell Transplantation: Safety, Efficacy, and Patient Outcomes. Literature Review

Autologous stem cell transplantation (auto-HSCT) is a part of the therapeutic strategy for various oncohematological diseases. The auto-HSCT procedure enables hematological recovery after high-dose chemotherapy, otherwise not tolerable, by the infusion of autologous hematopoietic stem cells. Unlike allogeneic transplant (allo-HSCT), auto-HSCT has the advantage of lacking acute-graft-versus-host disease (GVHD) and prolonged immunosuppression, however, these advantages are counterbalanced by the absence of graft-versus-leukemia. Moreover, in hematological malignancies, the autologous hematopoietic stem cell source may be contaminated by neoplastic cells, leading to disease reappearance. In recent years, allogeneic transplant-related mortality (TRM) has progressively decreased, almost approaching auto-TRM, and many alternative donor sources are available for the majority of patients eligible for transplant procedures. In adults, the role of auto-HSCT compared to conventional chemotherapy (CT) in hematological malignancies has been well defined in many extended randomized trials; however, such trials are lacking in pediatric cohorts. Therefore, the role of auto-HSCT in pediatric oncohematology is limited, in both first- and second-line therapies and still remains to be defined. Nowadays, the accurate stratification in risk groups, according to the biological characteristics of the tumors and therapy response, and the introduction of new biological therapies, have to be taken into account in order to assign auto-HSCT a precise role in the therapeutic strategies, also considering that in the developmental age, auto-HSCT has a clear advantage over allo-HSCT, in terms of late sequelae, such as organ damage and second neoplasms. The purpose of this review is to report the results obtained with auto-HSCT in the different pediatric oncohematological diseases, focusing on the most significant literature data in the context of the various diseases and discussing this data in the light of the current therapeutic landscape.

Biopathology of childhood, adolescent and young adult non-Hodgkin lymphoma

Mature non-Hodgkin lymphomas (NHL) in the childhood, adolescent and young adult (CAYA) population are rare and exhibit unique clinical, immunophenotypic and genetic characteristics. Application of large-scale unbiased genomic and proteomic technologies such as gene expression profiling and next generation sequencing (NGS) have led to enhanced understanding of the genetic basis for many lymphomas in adults. However, studies to investigate the pathogenetic events in CAYA population are relatively sparse. Enhanced understanding of the pathobiologic mechanisms involved in non-Hodgkin lymphomas in this unique population will allow for improved recognition of these rare lymphomas. Elucidation of the pathobiologic differences between CAYA and adult lymphomas will also lead to the design of more rational and much needed, less toxic therapies for this population. In this review, we summarize recent insights gained from the proceedings of the recent 7th International CAYA NHL Symposium held in New York City, New York October 20-23, 2022.

Diagnosis and management of rare paediatric Non-Hodgkin lymphoma

Mature B-cell lymphomas, (B- or T-cell) lymphoblastic lymphomas (LBL), and anaplastic large cell lymphoma (ALCL) correspond to about 90% of all non-Hodgkin lymphoma (NHL) cases occurring in children and adolescents. The remaining 10% encompass a complex group of entities characterized by low/very low incidences, paucity of knowledge in terms of underlying biology in comparison to their adult counterparts, and consequent lack of standardization of care, information on clinical therapeutic efficacy and long-term survival. At the Seventh International Symposium on Childhood, Adolescent and Young Adult NHL, organized on October 20-23, 2022, in New York City, New York, US, we had the opportunity to discuss clinical, pathogenetic, diagnostic, and treatment aspects of certain subtypes of rare B- or T-cell NHL and they will be the topic of this review.

How to recognize inborn errors of immunity in a child presenting with a malignancy: guidelines for the pediatric hemato-oncologist

Inborn errors of immunity (IEI) are a group of disorders caused by genetically determined defects in the immune system, leading to infections, autoimmunity, autoinflammation and an increased risk of malignancy. In some cases, a malignancy might be the first sign of an underlying IEI. As therapeutic strategies might be different in these patients, recognition of the underlying IEI by the pediatric hemato-oncologist is important. This article, written by a group of experts in pediatric immunology, hemato-oncology, pathology and genetics, aims to provide guidelines for pediatric hemato-oncologists on how to recognize a possible underlying IEI and what diagnostic tests can be performed, and gives some consideration to treatment possibilities.

Improving outcomes of childhood and young adult non-Hodgkin lymphoma: 25 years of research and collaboration within the framework of the European Intergroup for Childhood Non-Hodgkin Lymphoma

The European Intergroup for Childhood Non-Hodgkin Lymphoma (EICNHL) was established 25 years ago with the goal to facilitate clinical trials and research collaborations in the field both within Europe and worldwide. Since its inception, much progress has been made whereby major improvements in outcomes have been achieved. In this Review, we describe the different diagnostic entities of non-Hodgkin lymphoma in children and young adults describing key features of each entity and outlining clinical achievements made in the context of the EICNHL framework. Furthermore, we provide an overview of advances in biopathology with an emphasis on the role of biological studies and how they have shaped available treatments. Finally, for each entity, we describe future goals, upcoming clinical trials, and highlight areas of research that require our focus going forward.

A retrospective study on the clinicopathological and molecular features of 22 cases of natural killer/T-cell lymphoma in children and adolescents

Natural killer/T-cell lymphoma (NKTCL) in children and adolescents is a rare type of T/NK cell neoplasms. The aim of the present study was to analyze the clinicopathological and genetic features of this rare entity of lymphoma. We evaluated the clinical, histopathological and molecular features of 22 young people with NKTCL, including 15 males and 7 females, with a median age of 15 years. The results revealed that the nasal site was the most involved region while non-nasal sites were observed in 27.3% out of all cases. The tumor cells were composed of small‑sized to large cells and 19 (86.4%) cases exhibited coagulative necrosis. The neoplastic cells in all patients were positive for CD3 and the cytotoxic markers. Nineteen (86.4%) cases were positive for CD56. Reduced expression of CD5 was observed in all available cases. CD30 was heterogeneously expressed in 15 (75.0%) cases. All 22 patients were EBV positive. Seven (36.8%) out of all the 19 patients during the follow-up died of the disease, and the median follow‑up period was 44 months. Moreover, patients treated with radiotherapy/chemotherapy showed significantly inferior OS compared with the untreated patients. High mutation frequencies were detected including KMT2C (5/5), MST1 (5/5), HLA-A (3/5) and BCL11A (3/5), which involved in modifications, tumor suppression and immune surveillance. These results suggest that NKTCL in children and adolescents exhibits histopathological and immunohistochemical features similar to the cases in adults. Active treatment is necessary after the diagnosis of NKTCL is confirmed. Furthermore, genetic analyse may provide a deep understanding of this rare disease.

Management of Peripheral T-Cell Lymphoma in Children and Adolescents Including STAT 3 Mutation Hyper-IgE Syndrome: One Size Does Not Fit All

Peripheral T-cell lymphoma (PTCL) is a rare form of lymphoma in children with limited published data on treatment and lack of a uniformly accepted treatment algorithm. We retrospectively analyzed the data in children up to 18 years of age diagnosed to have PTCL from January 2016 to June 2020. The study included six children with a median age of 10 years, the youngest being a 7-month-old girl. According to the WHO-PTCL classification, three had PTCL-not otherwise specified (NOS), 2 had hepatosplenic TCL, and 1 had subcutaneous panniculitis-like TCL. All children had presented with advanced disease, 4 in St. Jude stage IV, 2 in St. Jude stage III. Three children received CHOEP chemotherapy including cyclophosphamide, doxorubicin, vincristine, prednisone, etoposide, while 1 child received CHOP. Two children received induction as per acute lymphoblastic leukemia followed by Bendamustine. Two patients succumbed to progressive disease, the infant with PTCL-NOS and 1 child with hepatosplenic TCL. Three children were in remission (median follow up of 44 mo). One child with PTCL-NOS Stage IV had an underlying STAT3 mutated hyperimmunoglobulin E syndrome and was in remission 12 months post a matched unrelated donor hematopoietic stem cell transplantation. He had grade 4 skin graft versus host disease and required extracorporeal photopheresis and ibrutinib, to which he had responded. CHOEP chemotherapy is well-tolerated and subcutaneous panniculitis-like TCL has the best prognosis thus far.

Pediatric Subcutaneous Panniculitis-like T-cell Lymphoma of the Orbit

Subcutaneous panniculitis-like T-cell lymphoma (SPTCL) is a rare and distinct subtype of peripheral T-cell lymphoma, representing <1% of all non-Hodgkin lymphomas. SPTCL usually arises in the fourth decade of life with multifocal involvement of the limbs and trunk. Orbital disease is uncommon. We present the youngest known case of orbital SPTCL in a 3-year-old child, where the diagnosis was initially confounded by a lower eyelid mass masquerading as preseptal cellulitis. MRI revealed a poorly defined anterior orbital mass. Immunophenotyping and histological analysis of an orbital biopsy specimen confirmed SPTCL, which was managed by the pediatric oncology team with multiagent chemotherapy. This case is unique due to the young age of presentation and primary orbital involvement. Nonresolving or atypical periorbital cellulitis needs to be investigated, as malignancy can mimic such conditions.

Durable Response in Relapsed Adolescent Peripheral T-cell Lymphoma: A Case Report and Review of the Literature

Peripheral T-cell lymphoma (PTCL) is an aggressive tumor, rarely seen in pediatrics or adolescent and young adults (AYAs) so there is no upfront or relapsed standard of care. The authors describe a 16-year-old with PTCL, treated with chemotherapy and autologous stem cell transplant. Upon relapse, he received ifosfamide, carboplatin, etoposide, and radiation with durable remission of 4 years. Data in pediatric/AYA PCTL continue to lack an understanding of the biology and microenvironment, the differences to adult patients, and a lack of adequate therapy. Targeted therapy may improve outcomes for children and AYAs with refractory or relapsed PTCL.

Molecular features of non-anaplastic peripheral T-cell lymphoma in children and adolescents

Non-anaplasticperipheral T-cell lymphomas (PTCL) are rare tumors in children, adolescents, and young adults (CAYA) with poor prognosis and scarce genetic data. We analyzed lymphoma tissue from 36 patients up to 18 years old with PTCL, not otherwise specified (PTCL-NOS), hepatosplenic T-cell lymphoma, Epstein-Barr virus (EBV)-positive T-lymphoproliferative diseases, subcutaneous panniculitis-like T-cell lymphoma, and other PTCL types. Twenty-three patients (64%) had at least one genetic variant detectable, including TET2, KMT2C, PIK3D, and DMNT3A. TP53 and RHOA variants, commonly found in adults, were not identified. Eight of 20 (40%) CAYA PTCL-NOS had no detectable mutations. The genetic findings suggest that CAYA PTCL differ from adult cases.

Update on Pediatric and Young Adult Mature Lymphomas

After acute leukemia and brain and central nervous system tumors, mature lymphomas represent the third most common cancer in pediatric patients. Non-Hodgkin lymphoma accounts for approximately 60% of lymphoma diagnoses in children, with the remainder representing Hodgkin lymphoma. Among non-Hodgkin lymphomas in pediatric patients, aggressive lymphomas, such as Burkitt lymphoma, diffuse large B-cell lymphoma, and anaplastic large cell lymphoma, predominate. This article summarizes the epidemiologic, histopathologic, and molecular features of selected mature systemic B-cell and T-cell lymphomas encountered in this age group.

Comparison of chemotherapy with or without asparaginase for extranodal nasal NK/T-cell lymphoma in children and adolescents

PURPOSE

As extranodal natural killer/T-cell lymphoma (ENKTL) occurs rarely in children and adolescents, standardized therapy is yet to be determined. This study aimed to describe the clinical features and determine the optimal chemotherapy regimen for childhood ENKTL.

METHODS

The treatment outcomes of radiotherapy combined with asparaginase-based (P-GEMOX or P-GMED) or asparaginase-absent chemotherapy regimens (CHOP, EPOCH, or NHL-BFM-90/95) in patients aged ≤18 years with newly diagnosed ENKTL from December 2006 to December 2018 were compared.

RESULTS

Among the 34 patients included in the study, 21 had stage I/II disease. The overall response rates of chemotherapy with or without asparaginase were 85.0% and 78.6%, respectively. With a median follow-up of 54 months, the 5-year event-free survival (EFS) rates of patients with stage I/II and III/IV disease were 66.2 ± 11.3% and 26.0 ± 12.8%, respectively (P = .027). In stage III/IV patients treated with asparaginase-based or asparaginase-absent regimens, the 5-year EFS rates were 40.0 ± 17.4% and 0%, respectively (P = .236). The 5-year EFS rates of stage III/IV patients who received or did not receive hematopoietic stem cell transplant were 66.7 ± 27.2% and 11.1 ± 10.5%, respectively (P = .054). In addition, chemotherapy-associated side effects were significantly less in patients treated with asparaginase-based regimens as compared to asparaginase-absent regimens in this cohort.

CONCLUSION

P-GEMOX and P-GMED regimens are effective and safe for treating childhood ENKTL.

Treatment and Outcome Analysis of 639 Relapsed Non-Hodgkin Lymphomas in Children and Adolescents and Resulting Treatment Recommendations

Simple Summary

Despite very poor survival, controversies remain in the treatment for refractory or relapsed non-Hodgkin lymphoma (r/r NHL) in children and adolescents. The current project identifies and reports international experience on re-induction treatment of r/r NHL, hematopoietic stem cell transplantation, risk factors associated with outcome, and suggests treatment recommendations.

Abstract

Despite poor survival, controversies remain in the treatment for refractory or relapsed pediatric non-Hodgkin lymphoma (r/r NHL). The current project aimed to collect international experience on the re-induction treatment of r/r NHL, hematopoietic stem cell transplantation (HSCT), risk factors associated with outcome, and to suggest treatment recommendations. Inclusion criteria were (i) refractory disease, disease progression or relapse of any NHL subtype except anaplastic large cell lymphoma, (ii) age < 18 years at initial diagnosis, (iii) diagnosis in/after January 2000. Data from 639 eligible patients were evaluable. The eight-year probability of overall survival was 34 ± 2% with highly significant differences according to NHL subtypes: 28 ± 3% for 254 Burkitt lymphoma/leukemia, 50 ± 6% for 98 diffuse large B-cell lymphomas, 57 ± 8% for 41 primary mediastinal large B-cell lymphomas, 27 ± 3% for 177 T-lymphoblastic lymphomas, 52 ± 10% for 34 precursor-B-cell lymphoblastic lymphomas and 30 ± 9% for 35 patients with rare NHL subtypes. Subtype-specific factors associated with survival and treatment recommendations are suggested. There were no survivors without HSCT, except in few very small subgroups. Conclusions: There is an urgent need to further improve survival in r/r NHL. The current study provides the largest real-world series, which underlines the role of HSCT and suggests treatment recommendations.

Hematopoietic Stem Cell Transplantation Positively Affects the Natural History of Cancer in Nijmegen Breakage Syndrome

PURPOSE

Nijmegen breakage syndrome (NBS) is a DNA repair disorder with a high predisposition to hematologic malignancies.

EXPERIMENTAL DESIGN

We describe the natural history of NBS, including cancer incidence, risk of death, and the potential effectiveness of hematopoietic stem cell transplantation (HSCT) in preventing both pathologies: malignancy and immunodeficiency.

RESULTS

Among 241 patients with NBS enrolled in the study from 11 countries, 151 (63.0%) patients were diagnosed with cancer. Incidence rates for primary and secondary cancer, tumor characteristics, and risk factors affecting overall survival (OS) were estimated. The cumulative cancer incidence was 40.21% ± 3.5% and 77.78% ± 3.4% at 10 years and 20 years of follow-up, respectively. Most of the tumors n = 95 (62.9%) were non-Hodgkin lymphomas. Overall, 20 (13.2%) secondary malignancies occurred at a median age of 18 (interquartile range, 13.7-21.5) years. The probability of 20-year overall survival (OS) for the whole cohort was 44.6% ± 4.5%. Patients who developed cancer had a shorter 20-year OS than those without malignancy (29.6% vs. 86.2%; P < 10^-5). A total of 49 patients with NBS underwent HSCT, including 14 patients transplanted before malignancy. Patients with NBS with diagnosed cancer who received HSCT had higher 20-year OS than those who did not (42.7% vs. 30.3%; P = 0.038, respectively). In the group of patients who underwent preemptive transplantation, only 1 patient developed cancer, which is 6.7 times lower as compared with nontransplanted patients [incidence rate ratio 0.149 (95% confidence interval, 0.138-0.162); P < 0.0001].

CONCLUSIONS

There is a beneficial effect of HSCT on the long-term survival of patients with NBS transplanted in their first complete remission of cancer.

Rare non-Hodgkin lymphoma of childhood and adolescence: A consensus diagnostic and therapeutic approach to pediatric-type follicular lymphoma, marginal zone lymphoma, and nonanaplastic peripheral T-cell lymphoma

Pediatric-type follicular (PTFL), marginal zone (MZL), and peripheral T-cell lymphoma (PTCL) account each for <2% of childhood non-Hodgkin lymphoma. We present clinical and histopathological features of PTFL, MZL, and few subtypes of PTCL and provide treatment recommendations. For localized PTFL and MZL, watchful waiting after complete resection is the therapy of choice. For PTCL, therapy is subtype-dependent and ranges from a block-like anaplastic large cell lymphoma (ALCL)-derived and, alternatively, leukemia-derived therapy in PTCL not otherwise specified and subcutaneous panniculitis-like T-cell lymphoma to a block-like mature B-NHL-derived or, preferentially, ALCL-derived treatment followed by hematopoietic stem cell transplantation in first remission in hepatosplenic and angioimmunoblastic T-cell lymphoma.

Primary Nonanaplastic Peripheral Natural Killer/T-Cell Lymphoma in Pediatric Patients-An Unusual Distribution Pattern of Subtypes

Peripheral NK/T-cell lymphoma (PNKTCL) represents a group of uncommon diagnoses for children in Western countries, and studies have often necessitated multiple institutions to assemble enough cases. We retrospectively analyzed 11 cases of nonanaplastic PNKTCL in children over 19 years at our institution with comparison to several published large multi-institutional studies. Patients included 9 males and 2 females of white (5), Native American (3), and Hispanic (3) background with 6 cases of extranodal NK/T-cell lymphoma, nasal type (EN-NKTL, 54.6%), 3 cases of peripheral T-cell lymphoma, not otherwise specified (PTCL-NOS, 27.2%), and 2 cases of systemic Epstein-Barr virus (EBV)-positive T-cell lymphoma of childhood (18.2%). Compared to the literature, our institution exceeded in frequency of total nonanaplastic PNKTCL (4.8% vs 0.9%-1.6%) with lesser relative incidence of PTCL-NOS (27.2% vs 42.9%-66.7%) and greater relative incidence of EN-NKTL (54.6% of cases vs 12.5%-47.6%), which significantly exceeded the literature's rate for Western institutions (13.5%). Potential influencing factors include population structure approximating those of non-Western countries with high EN-NKTL prevalence and the predisposition for EBV infection in this demography. These data suggest an uneven distribution of nonanaplastic PNKTCL in Western countries, and differential diagnoses may differ depending on practice location and associated patient population.

Treatment and prognosis of mature (non-anaplastic) T- and NK-cell lymphomas in childhood, adolescents, and young adults

Paediatric non-Hodgkin lymphomas (pNHL) are a diverse group of malignancies characterised by nodal and/or extranodal involvement. Less common pNHL forms include those derived from mature T- and natural killer (NK) cells. Much of our current understanding of paediatric mature (non-anaplastic) T/NK-cell lymphomas with respect to pathogenesis, diagnosis and treatment is extrapolated from adult literature. At the Sixth International Symposium on Childhood, Adolescent and Young Adult Non-Hodgkin Lymphoma, convened September 26-29, 2018 in Rotterdam, The Netherlands, some important aspects on diagnosis and outcomes of mature (non-anaplastic) T/NK-cell lymphoma in children and adolescents were discussed and will be reviewed in here.

Current Understanding and Future Research Priorities in Malignancy Associated With Inborn Errors of Immunity and DNA Repair Disorders: The Perspective of an Interdisciplinary Working Group

Patients with inborn errors of immunity or DNA repair defects are at significant risk of developing malignancy and this complication of their underlying condition represents a substantial cause of morbidity and mortality. Whilst this risk is increasingly well-recognized, our understanding of the causative mechanisms remains incomplete. Diagnosing cancer is challenging in the presence of underlying co-morbidities and frequently other inflammatory and lymphoproliferative processes. We lack a structured approach to management despite recognizing the competing challenges of poor response to therapy and increased risk of toxicity. Finally, clinicians need guidance on how to screen for malignancy in many of these predisposing immunodeficiencies. In order to begin to address these challenges, we brought together representatives of European Immunology and Pediatric Haemato-Oncology to define the current state of our knowledge and identify priorities for clinical and research development. We propose key developmental priorities which our two communities will need to work together to address, collaborating with colleagues around the world.

Early Onset of HTLV-1 Associated Myelopathy/Tropical Spastic Paraparesis (HAM/TSP) and Adult T-cell Leukemia/Lymphoma (ATL): Systematic Search and Review

Human T-cell lymphotropic virus type 1 (HTLV-1) is endemic in some regions and its vertical transmission occurs mainly through breastfeeding. About 10% of carriers develop associated diseases including HTLV-1 associated myelopathy/tropical spastic paraparesis (HAM/TSP), adult T-cell leukemia/lymphoma (ATL) and infectious dermatitis associated with HTLV-1 (IDH). We searched for available case reports of early-onset HAM/TSP and ATL to evaluate demographic and disease aspects in infantile-juvenile patients. In the reviewed literature, 27 HAM/TSP and 31 ATL cases were found. In almost all of them, the most likely route of transmission was through breastfeeding. ATL is rarely reported, notwithstanding it may be underestimated because T-cell lymphomas are not investigated for HTLV-1 infection in this age group. IDH was frequently associated with HAM/TSP. The investigation of HTLV-1 infection in pregnant women is an important matter of public health and should be mandatory in endemic countries.

Cutaneous Hematolymphoid and Histiocytic Proliferations in Children

This article focuses on cutaneous hematopoietic neoplasms that are more likely to be encountered in the pediatric age-group and includes both lymphoproliferative and histiocytic disorders. The cutaneous hematologic disorders in children have a different epidemiologic profile to what is seen during adulthood. Although mycosis fungoides is the most frequent form of cutaneous lymphoma in adults, it is very rare in children. Because lymphoblastic leukemias and lymphomas are more frequent in the pediatric setting, cutaneous leukemic infiltrates are relatively common in this age-group. Similarly, histiocytic disorders are more common in children, particularly Langerhans cell histiocytosis and juvenile xanthogranuloma. Notably, the histiocytic disorders have undergone significant modifications on their nomenclature in the basis of the molecular characteristics that are present in them. A summary of the most frequent cutaneous hematopoietic disorders in children will be discussed further in this review.

Non-Hodgkin lymphoma and pre-existing conditions: spectrum, clinical characteristics and outcome in 213 children and adolescents

Children and adolescents with pre-existing conditions such as DNA repair defects or other primary immunodeficiencies have an increased risk of non-Hodgkin lymphoma. However, large-scale data on patients with non-Hodgkin lymphoma and their entire spectrum of pre-existing conditions are scarce. A retrospective multinational study was conducted by means of questionnaires sent out to the national study groups or centers, by the two largest consortia in childhood non-Hodgkin lymphoma, the European Intergroup for Childhood non-Hodgkin Lymphoma, and the international Berlin-Frankfurt-Münster Study Group. The study identified 213 patients with non-Hodgkin lymphoma and a pre-existing condition. Four subcategories were established: a) cancer predisposition syndromes (n=124, 58%); b) primary immunodeficiencies not further specified (n=27, 13%); c) genetic diseases with no increased cancer risk (n=40, 19%); and d) non-classifiable conditions (n=22, 10%). Seventy-nine of 124 (64%) cancer predispositions were reported in groups with more than 20 patients: ataxia telangiectasia (n=32), Nijmegen breakage syndrome (n=26), constitutional mismatch repair deficiency (n=21). For the 151 patients with a known cancer risk, 5-year event-free survival and overall survival rates were 40%±4% and 51%±4%, respectively. Five-year cumulative incidences of progression/relapse and treatment-related death as a first event were 22%±4% and 24%±4%, respectively. Ten-year incidence of second malignancy was 24%±5% and 7-year overall survival of the 21 patients with a second malignancy was 41%±11%. Patients with non-Hodgkin lymphoma and pre-existing conditions have an inferior survival rate with a large proportion of therapy-related deaths compared to patients with non-Hodgkin lymphoma and no pre-existing conditions. They may require special vigilance when receiving standard or modified/reduced-intensity chemotherapy or when undergoing allogeneic stem cell transplantation.