Malignant Lymphomas |
1 Department of Pathology, Hematopathology Section and Lymph Node Registry, Christian-Albrechts University, Kiel
2 Institute of Human Genetics, Christian-Albrechts University, Kiel, & University Hospital Schleswig-Holstein, Campus Kiel
3 NHL-BFM Study Center, Department of Pediatric Hematology and Oncology, Justus-Liebig-University, Giessen
4 Departments of Pediatric Hematology and Oncology, University of Hannover
5 Childrens University Hospital, Christian-Albrechts University, Kiel, Germany
Correspondence: Wolfram Klapper, University-Hospital Schleswig-Holstein Hematopathology Section and Lymph Node Registry Kiel Arnold-Heller-Straße 3, Haus 14 24105 Kiel, Germany. E-mail: wklapper{at}path.uni-kiel.de
Background: Pediatric follicular lymphoma has recently been recognized as a novel variant of follicular lymphoma in the World Health Organization classification of lymphomas. Given the rarity of the disease, histopathological and genetic data on this type of lymphoma are still scarce.
Design and Methods: We analyzed 25 cases of pediatric follicular lymphoma (patients aged
18 years) by morphology, immunohistochemistry and interphase fluorescence in situ hybridization. All patients analyzed were treated within Non-Hodgkins Lymphoma - Berlin-Frankfurt-Münster (NHL-BFM) multicenter trials, and the cohort was representative of the German population.
Results: The genetic hallmark of adult follicular lymphoma, t(14;18)(q32;q21), was not detectable in any of the pediatric cases, although BCL2 protein was expressed in 55% of the latter cases. No correlation was found between BCL2 protein expression and outcome. Chromosomal breaks in the immunoglobulin heavy chain gene (IGH) and the BCL6 locus were detected in 5 of 17 and 1 of 18 cases, respectively. Patients with pediatric follicular lymphoma had long event-free survival and, in contrast to adult follicular lymphoma, the clinical course was not dominated by relapses. A simultaneous diffuse large B-cell lymphoma was frequently detected at initial diagnosis in children but did not indicate an aggressive clinical course.
Conclusions: Our data suggest that pediatric follicular lymphoma is a disease that differs from its adult counterpart both genetically and clinically.
Key words: pediatric follicular lymphoma, childhood lymphoma, pediatric diffuse large B-cell lymphoma, t(14;18).