Rare Pediatric Non-Hodgkin Lymphomas: A Report From Children's Oncology Group Study ANHL 04B1

Indolent B-cell non-Hodgkin lymphomas in children: high association with inborn errors of immunity

Indolent lymphomas are rare in children and mostly consist of pediatric type follicular (PTFL) and pediatric marginal zone lymphomas (PMZL) and extranodal marginal zone lymphoma (ENMZL). Twenty children with indolent lymphoma (10 PTFL, 6 PMZL, 3 ENMZL, 1 mixed type) among 307 Non-Hodgkin Lymphoma (NHL) were retrospectively evaluated. The mean age of the entire group was 10.4 ± 4.4 and was significantly lower in PTFL than in PMZL. Seven patients (35%) had an associated inborn error of immunity (IEI) which was higher than that seen in aggressive lymphomas (5.9%) (p < 0.0001). Seventeen patients (85%) had stage I/II disease. Two patients received no treatment after surgery. Eleven patients were treated only with 3-6 courses of rituximab. Four patients received 3-6 courses of R-CHOP protocol. The prognosis was excellent Five years overall and event-free survivals were 100% and 85%, respectively.

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.

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.

Diagnosis and management of cutaneous lymphomas and lymphoid proliferations in children, adolescents and young adults (CAYA)

Cutaneous lymphomas and lymphoid proliferations (LPD) in children, adolescents, and young adults (CAYA) are a heterogeneous group of lymphoid neoplasms that present formidable diagnostic challenges to clinicians and pathologists alike. Although rare overall, cutaneous lymphomas/LPD occur in real-world settings and awareness of the differential diagnosis, potential complications, and various therapeutic approaches will help ensure the optimal diagnostic work-up and clinical management. Lymphomas/LPD involving the skin can occur as primary cutaneous disease in a patient that characteristically has lymphoma/LPD confined to the skin, or as secondary involvement in patients with systemic disease. This review will comprehensively summarize both primary cutaneous lymphomas/LPD that occur in the CAYA population as well as those CAYA systemic lymphomas/LPD with propensity for secondary cutaneous involvement. Focus on the most common primary entities occurring in CAYA will include lymphomatoid papulosis, primary cutaneous anaplastic large cell lymphoma, mycosis fungoides, subcutaneous panniculitis-like T-cell lymphoma, and hydroa vacciniforme lymphoproliferative disorder.

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.

Primary central nervous system lymphoblastic B cell lymphoma located at cerebellum in a child: A case report and literature review

INTRODUCTION

Primary central nervous system lymphoma (PCNSL) is extremely rare in pediatric population. We reported a case of PCNSL in a 3-year-old girl and reviewed the literature in the past three decades.

CASE PRESENTATION

A 3-year-old girl presented with gait disturbance. A contrast-enhanced magnetic resonance image of the brain showed a solitary bulky mass in the left cerebellar hemisphere, hydrocephalus and cerebellar tonsillar hernia. Surgical resection was performed and the patient was diagnosed with primary central nervous system lymphoblastic B cell lymphoma. Then the patient received regular chemotherapy, including 6 cycles of chemotherapy containing high-dose methotrexate (HD-MTX). The patient remains alive 15 months after the diagnosis with no evidence of active disease, but suffered twice chronic subdural hematoma, which was treated by burr hole drainage.

CONCLUSION

Lymphoblastic B cell lymphoma is a rare histologic subtype of pediatric PCNSL. Chemotherapy containing HD-MTX remains the most effective treatment. The patient should avoid head impact after surgical resection of the tumor to prevent chronic subdural hematoma.

Fine needle biopsy of pediatric-type follicular lymphoma-Cytology, flow cytometry and FISH pattern: A case report

Pediatric-type follicular lymphomas are rare lymphomas, affecting mostly children and young adults. These are characterized by an excellent prognosis, despite their conservative therapeutic approach. Recognized as an entity in the most recent 2016 WHO classification of tumors of hematopoietic and lymphoid tissues, its diagnosis is based on the recognition of an exclusively nodular architecture, thus conditioning the possibility of a cytological diagnosis. It is thus not odd, the scant literature found on the cytological approach to these lesions. Herein we describe a case of a pediatric-type follicular lymphoma, first approached through fine needle biopsy. The case is thoroughly discussed from a cytologic, immunophenotypic, and molecular point of view. Differential diagnoses are discussed. The final diagnosis was performed on histology.

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.

Primary cutaneous follicle center lymphoma in a 16-year-old girl

In the pediatric and adolescent age group, primary cutaneous lymphomas are rare, especially cutaneous B-cell lymphomas. According to the World Health Organization, the three main subtypes of primary cutaneous B-cell lymphomas are primary cutaneous marginal zone B-cell lymphoma (PCMZL), primary cutaneous follicle center lymphoma (PCFCL), and primary cutaneous diffuse large B-cell lymphoma, leg type. We present an extraordinary case of PCFCL arising in a 16-year-old female, only the sixth case of PCFCL to be reported in the literature in a patient less than 20 years old. Although PCMZL was considered in this case, the finding of lambda light chain restriction in the BCL-6 and CD10 positive population of lymphocytes established the diagnosis of primary cutaneous follicle center lymphoma. Not many data currently exist on the prognosis of PCFCL in young individuals, but adult PCFCL has a good prognosis with an indolent course and 5-year survival rates over 95%. Because of its uncommon manifestation in young patients, the diagnosis of PCFCL is often delayed or missed. This case is presented to raise awareness of PCFCL in the pediatric/ adolescent population and to contribute to the ongoing research of this condition.

Primary central nervous system lymphoma: initial features, outcome, and late effects in 75 children and adolescents

Children with PCNSL and no immunodeficiency have a good outcome when treated by a histological subtype–driven and radiation-free protocol. New treatment guidelines are needed for PCNSL in children and adolescents with an underlying immunodeficiency.

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.

30 Years of Experience with Non-Hodgkin Lymphoma in Children and Adolescents: a retrospective cohort study

OBJECTIVE

Describe the clinical and demographic characteristics of pediatric patients with non-Hodgkin's lymphoma (NHL) enrolled in a tertiary unit of Pediatric Hematology between 1982-2015.

PATIENTS AND METHODS

A retrospective cohort study of 140 patients aged 16 years or less with NHL. Demographic characteristics, data on diagnosis, and outcomes were analyzed. The overall survival (OS) analysis and stratification by the most frequent histological subtypes were performed using the Kaplan-Meier method.

RESULTS

One hundred and thirty-six patients with de novo NHL and four with NHL as a second malignancy were analyzed. The median age at diagnosis was 6.4 years (interquartile range, 4.2 to 11.1 years); 101 patients were males. Four patients had primary immunodeficiency, four had human immunodeficiency virus, two post-liver transplantation, and one had autoimmune lymphoproliferative syndrome. The most frequent histological type was NHL of mature B- cell (B-NHL-B; 67.1%), with Burkitt's lymphoma being the most frequent subtype, and lymphoblastic lymphoma (LBL, 21.4%). The main clinical manifestation at the diagnosis was abdominal tumors (41.4%). During the follow-up time, 13 patients relapsed, but five of them reached a second remission. Thirty-five patients died, and 103 remained alive in clinical remission. No contact was possible for two patients. The OS at 5 years was 74.5% (± 3.8%). The OS estimated for patients with LBL, NHL-B, and the remaining was 80.4%±7.9%, 72.8%±4.7%, and 74.5%±11%, respectively (P = 0.58).

CONCLUSION

Our results are comparable with cohorts from other middle-income countries.

An unusual case of pediatric-type follicular lymphoma: A case report

RATIONALE

Pediatric-type follicular lymphoma (PTFL) is a rare neoplasm with features that differ from those of adult-type follicular lymphoma. Compared to patients with adult-type follicular lymphoma, PTFL patients often show an excellent response. Preoperative diagnosis is challenging and, therefore, an accurate diagnosis is based on the findings of postoperative pathological examination and immunohistochemistry.

PATIENT CONCERNS

A 13-year-old boy presented with a slow-growing mass on the right side of his neck.

DIAGNOSES

The patient was diagnosed with PTFL based on the findings of histopathological examination and immunohistochemistry.

INTERVENTION

The mass was completely resected.

OUTCOMES

After 12 months of postoperative follow-up, the patient achieved good recovery without recurrence.

LESSONS

The optimal treatment for PTFL has not yet been defined. However, patients with PTFL always show satisfactory prognoses, regardless of treatment strategy (targeted radiotherapy, multiagent chemotherapy, or "watch and wait" strategy). Clinically, pathological and immunohistochemical analyses are necessary in the diagnoses of PTFL cases, especially for distinguishing PTFL from reactive follicular hyperplasia, to avoid unnecessary treatment.

Prognostic Factors and Treatment Outcome of Pediatric Anaplastic Large Cell Lymphoma Treated at the Children Cancer Hospital Egypt

INTRODUCTION

The aim of the current study is to report the epidemiologic data, response rate, treatment outcome, and overall survival of anaplastic large cell lymphoma (ALCL) patients during the 8-year period.

PATIENTS AND METHODS

A retrospective study included all patients with newly diagnosed ALCL from July 2007 till December 2015.

RESULTS

A total of 48 patients were enrolled. The majority (66.7%) were male individuals. Twenty-one patients (43.7%) were low stage I or II, whereas 27 (56.2%) had advanced stage III or IV. Two patients (4.2%) died during induction chemotherapy. Disease status at last follow-up showed 35 patients (72.9%) in complete remission, 5 (10.5%) relapse, and 5 disease progression. The median time to relapse was 17.2 months. Four patients (8.4%) were salvaged by high-dose chemotherapy ifosphamide, carboplatine, etoposide followed by autologous hematopoietic stem cell transplantation, whereas 5 (10.5%) died out of disease progression. The 5-year overall survival and event-free survival were 81.2% and 68.6%, respectively. Median FU period was 58.7 month. Multivariate analysis included age, sex, stage, and response to chemotherapy and showed no statistical significance.

CONCLUSION

Treatment of ALCL according to the Children's Oncology Group ANHL 0131 protocol is well tolerated. The relapsing patient could be salvaged by high-dose chemotherapy and autologous hematopoietic stem cell transplantation.

Pediatric Subcutaneous Panniculitis-like T-Cell Lymphoma With Hemophagocytosis Showing Complete Resolution With the BFM90 Protocol: Case Report and Review of Literature

Subcutaneous panniculitis-like T-cell lymphoma (SPTCL) is a distinct subtype of peripheral T-cell lymphoma associated with aggressive clinical behavior. Since its original description, it has continued to be a rare disease, and <200 cases have been reported in literature. We report an 11-year-old boy who presented with SPTCL and hemophagocytic lymphohistiocytosis (HLH) and responded to high-dose multiagent chemotherapy. He presented with steroid refractory erythematous, raised plaques over his face, trunk, and limbs over a period of 15 months treated elsewhere. Repeat evaluation in our center was consistent with SPTCL with features of HLH. He was initiated on therapy with the BFM90 protocol, which led to complete morphologic and biochemical remission. No single-best treatment regimen has been described for SPTCL with HLH in literature, and high-dose chemotherapy has shown good long-term remissions in the literature. The presence of SPTCL with HLH and systemic symptoms should prompt treatment with high-dose multiagent chemotherapy rather than Cyclophosphamide, Vincristine, Adriamycin, Prednisolone-like therapy. BFM90 is one such regimen that is well tolerated, and it can induce significant clinical and biochemical responses.

IRF4 translocation status in pediatric follicular and diffuse large B-cell lymphoma patients enrolled in Children's Oncology Group trials

Large B-cell lymphoma with IRF4 rearrangement is a provisional entity in the 2017 World Health Organization classification. In order to characterize these lymphomas in children from the United States, IRF4 FISH and immunohistochemical stains were performed on 32 follicular lymphoma and diffuse large B-cell lymphoma (DLBCL) from Children's Oncology Group studies. Two DLBCLs (6%) had IRF4 rearrangements, one involving the ileocecal valve and another involving the tonsil and cerebrospinal fluid. Both cases had strong, diffuse IRF4/MUM1 immunohistochemical staining, which may be a pathologic clue to the diagnosis. Reclassification of these cases may have prognostic and therapeutic implications.

Rare mature B-cell lymphomas in children and adolescents

Pediatric-type follicular lymphoma (PTFL), pediatric nodal marginal zone lymphoma (pnMZL), and large B-cell lymphoma (LBCL) with IRF4 rearrangement have been introduced into the current World Health Organization (WHO) classification. They account for 5% to 10% of mature B-cell lymphomas in children and adolescents. Both PTFL and pnMZL predominantly affect male adolescents and usually present with localized lymphadenopathy in the head and neck region. The cells within the follicles of PTFL typically show high-grade cytology, IGH monoclonality and lack the t(14;18) chromosomal alteration. In contrast, pnMZL is characterized by progressive transformation of germinal center (PTGC)-like features and interfollicular proliferation of the cells with expansion of the marginal zones with diffuse areas. Watch and wait after complete resection seems an adequate therapy with chemotherapy restricted to incompletely resected disease. All children with PTFL and pnMZL reported, so far, survived. B-cell lymphomas presenting in the Waldeyer's ring are characterized by the expression of IRF4/MUM1 and often associated with IRF4 rearrangements. Because of the frequent diffuse component, treatment often follows current protocols for mature B-NHL. The prognosis is excellent.

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.

Impact of biobanks on research outcomes in rare diseases: a systematic review

Background

Alleviating the burden of rare diseases requires research into new diagnostic and therapeutic strategies. We undertook a systematic review to identify and compare the impact of stand-alone registries, registries with biobanks, and rare disease biobanks on research outcomes in rare diseases.

Methods

A systematic review and meta-aggregation was conducted using the preferred reporting items for systematic reviews and meta-analyses (the PRISMA statement). English language publications were sourced from PubMed, Medline, Scopus, and Web of Science. Original research papers that reported clinical, epidemiological, basic or translational research findings derived from data contained in stand-alone registries, registries with biobanks, and rare disease biobanks were considered. Articles selected for inclusion were assessed using the critical appraisal instruments by JBI-QARI. Each article was read in its entirety and findings were extracted using the online data extraction software from JBI-QARI.

Results

Thirty studies including 28 rare disease resources were included in the review. Of those, 14 registries were not associated to biobank infrastructure, 9 registries were associated with biobank infrastructure, and 6 were rare disease biobank resources. Stand-alone registries had the capacity to uncover the natural history of disease and contributed to evidence-based practice. When annexed to biobank infrastructure, registries could also identify and validate biomarkers, uncover novel genes, elucidate pathogenesis at the Omics level, and develop new therapeutic strategies. Rare disease biobanks in this review had similar capacity for biological investigations, but in addition, had far greater sample numbers and higher quality laboratory techniques for quality assurance processes.

Discussion

We examined the research outcomes of three specific populations: stand-alone registries, registries with biobanks, and stand-alone rare disease biobanks and demonstrated that there are key differences among these resources. These differences are a function of the resources’ design, aims, and objectives, with each resource having a distinctive and important role in contributing to the body of knowledge for rare disease research. Whilst stand-alone registries had the capacity to uncover the natural history of disease, develop best practice, replace clinical trials, and improve patient outcomes, they were limited in their capacity to conduct basic research. The role of basic research in rare disease research is vital; scientists must first understand the pathways of disease before they can develop appropriate interventions. Rare disease biobanks, on the other hand (particularly larger biobanks), had the key infrastructure required to conduct basic research, making novel Omics discoveries, identify and validate biomarkers, uncover novel genes, and develop new therapeutic strategies. However, these stand-alone rare disease biobanks did not collect comprehensive data or impact on clinical observations like a rare disease registry.

Rare disease research is important not only for rare diseases, but also for also common diseases. For example, research of low-density lipoprotein (LDL)-receptors in the rare disease known as familial hypercholesterolemia led to the discovery of statins, a drug therapy that is now used routinely to prevent heart disease.

Conclusions

Rare diseases are still under-researched worldwide. This review made the important observation that registries with biobanks had the function of both stand-alone registries (the capacity to collect comprehensive clinical and epidemiological data) and stand-alone rare disease biobanks (the ability to contribute to Omics research). We found registries with biobanks offer a unique, practical, cost-effective, and impactful solution for rare disease research. Linkage of stand-alone registries to rare disease biobanks will provide the appropriate resources required for the effective translation of basic research into clinical practice. Furthermore, facilitators such as collaboration, engagement, blended recruitment, pro-active marketing, broad consent, and “virtual biobank” online catalogues will, if utilised, add to the success of these resources. These important observations can serve to direct future rare diseases research efforts, ultimately improve patient outcomes and alleviate the significant burden associated with rare disease for clinicians, hospitals, society, and most importantly, the patients and their families.

Electronic supplementary material

The online version of this article (10.1186/s13023-018-0942-z) contains supplementary material, which is available to authorized users.

Children and adolescents with marginal zone lymphoma have an excellent prognosis with limited chemotherapy or a watch-and-wait strategy after complete resection

Data on management of pediatric marginal zone lymphoma (MZL) are scarce. This retrospective study assessed characteristics and outcome in 66 patients who were <18 years old. Forty-four (67%) had an extranodal MZL (EMZL), 21 (32%) a nodal MZL (NMZL), and one patient a splenic MZL. Thirty-three patients (50%) received a variable combination of adjuvant chemotherapy/immunotherapy/radiotherapy, while the remainder, including 20 of 21 with NMZL, entered an active observation period. Overall survival was excellent (98 ± 2%), although 11 patients relapsed (17%; NMZL, n = 1; EMZL, n = 10), seven after any therapy and four after complete resection only. In conclusion, outcome of NZML, in particular, seems to be excellent after (in)complete resection and observation only.

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.

Beyond Endemic Burkitt Lymphoma: Navigating Challenges of Differentiating Childhood Lymphoma Diagnoses Amid Limitations in Pathology Resources in Lilongwe, Malawi

Background. Although Burkitt lymphoma (BL) is the most common childhood lymphoma in sub-Saharan Africa, Hodgkin lymphoma (HL) and other non-Hodgkin lymphomas occur. Diagnosing non-jaw mass presentations is challenging with limited pathology resources. Procedure. We retrospectively analyzed 114 pediatric lymphomas in Lilongwe, Malawi, from December 2011 to June 2013 and compared clinical versus pathology-based diagnoses over two time periods. Access to pathology resources became more consistent in 2013 compared with 2011-2012; pathology interpretations were based on morphology only. Results. Median age was 8.4 years (2.1-16.3). The most common anatomical sites of presentation were palpable abdominal mass 51%, peripheral lymphadenopathy 35%, and jaw mass 34%. There were 51% jaw masses among clinical diagnoses versus 11% in the pathology-based group (P < .01), whereas 62% of pathology diagnoses involved peripheral lymphadenopathy versus 16% in the clinical group (P < .01). The breakdown of clinical diagnoses included BL 85%, lymphoblastic lymphoma (LBL) 9%, HL 4%, and diffuse large B-cell lymphoma (DLBCL) 1%, whereas pathology-based diagnoses included HL 38%, BL 36%, LBL 15%, and DLBCL 11% (P < .01). Lymphoma diagnosis was pathology confirmed in 19/66 patients (29%) in 2011-2012 and 28/48 (60%) in 2013 (P < .01). The percentage of non-BL diagnoses was consistent across time periods (35%); however, 14/23 (61%) non-BL diagnoses were pathology confirmed in 2011-2012 versus 16/17 (94%) in 2013. Conclusions. Lymphomas other than Burkitt accounted for 35% of childhood lymphoma diagnoses. Over-reliance on clinical diagnosis for BL was a limitation, but confidence in non-BL diagnoses improved with time as pathology confirmation became standard. Increased awareness of non-BL lymphomas in equatorial Africa is warranted.

Pediatric-type Follicular Lymphoma and Pediatric Nodal Marginal Zone Lymphoma: Recent Clinical, Morphologic, Immunophenotypic, and Genetic Insights

Pediatric-type follicular lymphoma and pediatric nodal marginal zone lymphoma are 2 of the rarest B-cell lymphomas. Although they are both predominantly seen in children, they can manifest in the adult population as well. Our understanding of these lymphomas has advanced rapidly in recent years such that we not only have a firm grasp of the morphologic and immunophenotypic findings, but also have a deeper insight into critical genetic and molecular pathways of these diseases. This review will cover the clinical and pathologic characteristics, treatment, prognosis, and important differential diagnoses of these entities.

Management of primary central nervous system lymphoma in children

A 14-year-old boy with no significant past medical history presents with headaches and vomiting and is found to have a 2 × 3-cm left parietal lobe mass. A stereotactic biopsy reveals diffuse large B-cell lymphoma (DLBCL). Cerebrospinal fluid cytology, as well as bone marrow biopsies are negative, and a whole-body positron emission tomography/computed tomography scan does not demonstrate other areas of disease. The primary medical team asks how you would treat this patient.

Nodal marginal zone lymphoma: Clinical features, diagnosis, management and treatment

Nodular marginal zone lymphoma (NMZL) is a small B-cell lymphoma involving only lymph nodes and is the least common form of MZL constituting about 10% of cases. Patients usually present with advanced disease which must be distinguished from extranodal MZL with lymph node spread. NMZL shares cytological and immunophenotypic features with MALT and splenic MZL, but has a less favorable prognosis than these two categories. It occurs mostly in adults and pediatric cases are rare. Different therapeutic approaches have been used in NMZL, but because of the small patient numbers involved, more definitive treatment is still anticipated. Recent studies suggest that it probably represents a separate entity within the broader indolent lymphoma category. In NMZL there is an emerging need to utilize novel agents, already available for indolent lymphomas. Prospective studies are required to evaluate their therapeutic efficacy for NMZL in the future.

Primary Cutaneous Lymphomas in Children and Adolescents

Primary cutaneous lymphomas are rare in children and mostly represented by mycosis fungoides and CD30(+) lymphoproliferative disorders. Most pediatric cutaneous lymphomas have similar clinical/pathological features as their adult counterparts, particularly the T-cell subtypes. With regard to outcome, adult cutaneous mature T-cell lymphomas have a tendency to progression, while this appears to be relatively infrequent in children. The outcome of cutaneous B-cell lymphomas depends on subtype, with the B-lymphoblastic entity being associated with similar outcomes to precursor B acute lymphoblastic leukemia, while there are insufficient data on other entities. The diagnosis and treatment of these patients require a close collaboration between experienced pediatric pathologists, dermatologists, and oncologists. Prospective collection of longitudinal clinical and biological data from children with these rare lymphomas is needed to better understand their biological and clinical behavior and to ultimately discover the best therapeutic strategies.

A study of the mutational landscape of pediatric-type follicular lymphoma and pediatric nodal marginal zone lymphoma

Pediatric-type follicular lymphoma and pediatric marginal zone lymphoma are two of the rarest B-cell lymphomas. These lymphomas occur predominantly in the pediatric population and show features distinct from their more common counterparts in adults: adult-type follicular lymphoma and adult-type nodal marginal zone lymphoma. Here we report a detailed whole-exome deep sequencing analysis of a cohort of pediatric-type follicular lymphomas and pediatric marginal zone lymphomas. This analysis revealed a recurrent somatic variant encoding p.Lys66Arg in the transcription factor interferon regulatory factor 8 (IRF8) in 3 of 6 cases (50%) of pediatric-type follicular lymphoma. This specific point mutation was not detected in pediatric marginal zone lymphoma or in adult-type follicular lymphoma. Additional somatic point mutations in pediatric-type follicular lymphoma were observed in genes involved in transcription, intracellular signaling, and cell proliferation. In pediatric marginal zone lymphoma, no recurrent mutation was identified; however, somatic point mutations were observed in genes involved in cellular adhesion, cytokine regulatory elements, and cellular proliferation. A somatic variant in AMOTL1, a recurrently mutated gene in splenic marginal zone lymphoma, was also identified in a case of pediatric marginal zone lymphoma. The overall non-synonymous mutational burden was low in both pediatric-type follicular lymphoma and pediatric marginal zone lymphoma (4.6 mutations per exome). Altogether, these findings support a distinctive genetic basis for pediatric-type follicular lymphoma and pediatric marginal zone lymphoma when compared with adult subtypes and to one another. Moreover, identification of a recurrent point mutation in IRF8 provides insight into a potential driver mutation in the pathogenesis of pediatric-type follicular lymphoma with implications for novel diagnostic or therapeutic strategies.