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

An Unusual Case of Extranodal Marginal Zone Lymphoma Mimicking Abdominal Cocoon Syndrome in an Adolescent Patient

Extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue (MALT lymphoma) is an indolent non-Hodgkin lymphoma rarely seen in pediatric patients. MALT lymphoma most commonly involves the gastrointestinal tract or peri-orbital tissues, potentially as sequela of chronic antigenic stimulation or immune dysregulation. Rare cases of MALT lymphoma arising from the gynecologic tract have been reported in older adult patients. We present the unique case of a 16-year-old postpubescent female with MALT lymphoma localized to the gynecologic tract, who initially presented with abdominal fullness, abnormal uterine bleeding, and obstructive acute kidney injury secondary to urinary outflow obstruction. Intraoperatively, dense fibrosis of the uterus and left fallopian tube was noted which mimicked abdominal cocoon syndrome. She was treated with 6 cycles of bendamustine and rituximab with complete anatomic and metabolic remission. In this report we highlight a very unusual presentation of a rare malignancy in the pediatric population as well as unique treatment considerations given this patient's young age and tumor location.

Chemokine Receptor PET/CT Provides Relevant Staging and Management Changes in Marginal Zone Lymphoma

Because of gastral and extranodal manifestations, guideline-compatible diagnostic work-up of marginal zone lymphoma is challenging. We aimed to determine the diagnostic performance of C-X-C motif chemokine receptor 4 (CXCR4)-directed PET/CT compared with routine diagnostics, along with PET/CT-based retrospective changes in therapeutic management. The predictive potential of the PET signal was also investigated, and the number of patients eligible for CXCR4-directed radioligand therapy in a theranostic setting was determined. Methods: For this study, 100 marginal zone lymphoma patients underwent CXCR4-directed PET/CT. We compared staging results and treatment decisions from molecular imaging with respective results from guideline-compatible work-up (CT, esophagogastroduodenoscopy, and bone marrow-derived biopsy). Prognostic performance of the in vivo CXCR4 PET signal for progression-free survival (PFS) was evaluated (using log-rank test and Kaplan-Meier curves). Results: Relative to CT, CXCR4-directed imaging led to Ann Arbor (AA) staging changes for 27 of 100 patients (27.0%). Among those, clinically relevant upstaging from AA I or AA II to AA III or AA IV was observed for 23 patients (85.2%), along with respective changes in therapeutic management (escalation, 6/23 [26.1%]; deescalation, 17/23 [73.9%]). CXCR4 PET/CT yielded diagnostic accuracy of 94.0% relative to esophagogastroduodenoscopy and 76.8% relative to bone marrow-derived biopsy. An increased CXCR4 PET signal was linked to shorter PFS (707 d vs. median PFS not reached; hazard ratio, 3.18; 95% CI, 1.37-7.35; P = 0.01). CXCR4-directed radioligand therapy would have been feasible for 18 of 100 patients (18.0%). Conclusion: Relative to CT, CXCR4-directed PET/CT led to AA changes for 27 of 100 patients. Chemokine receptor PET/CT may improve current diagnostic algorithms and influence management relative to CT alone, potentially obviating some biopsies.

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.

Pediatric-Type Indolent B-Cell Lymphomas With Overlapping Clinical, Pathologic, and Genetic Features

Pediatric-type follicular lymphoma (PTFL) and pediatric nodal marginal zone lymphoma (PNMZL) are rare pediatric-type indolent B-cell lymphomas (PedIBCL) that differ clinicopathologically from their adult counterparts. Accurate diagnosis is important to avoid overtreatment but is often challenging. The mutational landscape of PTFL is known and may aid diagnosis, but the genetic features of PNMZL are not well understood. We analyzed 21 cases of PedIBCL according to their clinicopathologic findings and classified them into PTFL (n=11), PNMZL (n=2), and "mixed type" tumors (n=8) showing ambiguous histology. We also analyzed 2 cases of adult B-cell lymphomas showing features of PedIBCL. Targeted sequencing of 121 lymphoma-related genes was performed. The median age of PedIBCL patients was 16 years (range: 3 to 47), and all but 1 PTFL patient were male. All patients presented with limited-stage disease, and only 1 relapsed. There were no significant differences in clinical features among the 3 PedIBCL groups. The most frequently mutated genes were MAP2K1 , TNFRSF14 , KMT2C , IRF8 , and NOTCH2 . The genetic features of all groups were similar to the established mutational landscape of PTFL. The 2 adult B-cell lymphomas cases also had MAP2K1 , TNFRSF14 , and IRF8 mutations, but the clinical features were not typical of PedIBCL. In summary, this study demonstrated that PTFL and PNMZL are similar diseases with overlapping clinical, pathologic, and genetic features; mixed type tumors can also occur. Atypical adult cases with similar histologic features were also observed. Therefore, the disease spectrum of PedIBCL may be much broader than is currently believed.

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.

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.

Lymphomas of the head and neck region: an update

The field of haematopathology is rapidly evolving and for the non-specialized pathologist receiving a specimen with the possibility of a lymphoid malignancy may be a daunting experience. The coincidence of the publication, in 2017, of the WHO monographies on head and neck and haematopoietic and lymphoid tumours prompted us to write this review. Although not substantially different from lymphomas elsewhere, lymphomas presenting in this region pose some specific problems and these are central to the review. In addition, differences in subtype frequency and morphological variations within the same entity are discussed. The difficulty in diagnosis related to some specimens led us to briefly mention common subtypes of systemic lymphomas presenting in the head and neck region.

Mature B-NHL in children, adolescents and young adults: current therapeutic approach and emerging treatment strategies

Mature B cell lymphomas account for approximately 60% of all cases of non-Hodgkin lymphoma (NHL) in children and adolescents and includes Burkitt lymphoma (BL), diffuse large B cell lymphoma (DLBCL) and other less common histologies. The outcome for patients treated with modern regimens in resource-intensive settings is excellent. Improvements in care have been accomplished through enhanced supportive therapy, including tumour lysis management and incremental refinement of chemotherapy backbones via cooperative group clinical trials in which patients receive risk group-specific intensive chemotherapy. More recent trials have established the safety and efficacy of immunotherapy. Ongoing work is required to address the substantial burden of acute therapy-related toxicity, as well as the identification of effective therapies for those patients with relapsed and refractory disease, for whom outcomes remain very poor. In this review we will summarize the results from recent therapeutic clinical trials, describe the evidence to support the inclusion of rituximab and review the rationale for the investigation of several new categories of novel agents for mature B cell lymphomas in children and adolescents.

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.