Primary mediastinal B‐cell lymphoma in the pediatric patient: Can a rational approach to therapy be based on adult studies?

Abstract

The literature on adult and pediatric primary mediastinal B-cell lymphoma (PMBCL) was reviewed and compared. Biologically, adult PMBCL has more similarities to Hodgkin Lymphoma (HL) than diffuse large B-cell lymphoma (DLBCL). Pediatric studies suggest that the biology is similar to that in adults. Median age of children is 14.3 years and the overall survival (OS) is reported as 78.6% and event-free survival (EFS) as 67.4%. Adverse prognostic factors included LDH >500 and mass size over 10 cm, with a trend towards better survival in younger patients. Studies in adults show better survival with intensified chemotherapy and the addition of rituximab. Data on the use of radiation therapy show improved CR rates and survival with addition of involved field radiation therapy (IFRT). Positron emission tomography (PET) with computerized tomography (CT) imaging response-assessment after two courses and at therapy-end may allow for the rational use of IFRT in pediatric/adolescent patients who are more susceptible to development of adverse late effects.

Clinical, pathological and genetic features of primary mediastinal large B-cell lymphomas and mediastinal gray zone lymphomas in children

“…This study did not find any indication of biological differences between childhood and adult PMBCL, as had been speculated in previous publications discussing therapeutic aspects of pediatric PMBCL. 16 However, more comprehensive molecular genetic profiling will be needed in future studies to determine conclusively whether or not there are molecular differences between the two age groups. Interestingly, lymphomas morphologically and immunophenotypically resembling PMBCL can harbor chromosomal translocations involving the MYC locus, as we found in one case in our series.…”

“…2,16 Compared to pediatric treatment regimens, adult protocols include higher cumulative doses of doxorubicin, etoposide, alkylating agents and bleomycin, but little or no methotrexate. 15,16,22 Furthermore, radiation therapy has been administered in addition to chemotherapy in most adult series, although the role of radiation remains a matter of debate.…”

“…15 Improving the treatment outcome in children suffering from PMBCL is, therefore, a major challenge for pediatric oncologists. 16 The clinical presentation of patients with PMBCL is comparable in adult and pediatric series. 2 However, the frequency of MGZL in children and adolescents has not been studied in large series.…”

Molecular distinctions between pediatric and adult mature B-cell non-Hodgkin lymphomas identified through genomic profiling

“…27 In contrast with other DLBCL subtypes, therapeutic outcomes are worse for children with PMBL compared with adult patients. 28,29 By immunohistochemistry, pediatric DLBCL was shown to consist predominantly of the GCB subtype, 13,14 which may account for the favorable prognosis in this age group. However, a GEP-based molecular classification of pediatric DLBCL is currently lacking.…”

Imaging of the Pediatric Thymus and Thymic Disorders

“…DLBCL is composed of two subtypes: primary mediastinal B-cell lymphoma (PMBL) and disseminated disease. PMBL was first recognized as a distinct subtype of DLBCL in the 1980s (Johnson and Davies 2008;Attias et al 2009). This tumor arises from the thymic medullary B-cells.…”