title: Follicular variant of peripheral T cell lymphoma with mediastinal involvement in a child: a case report.
abstract: Peripheral T cell lymphomas are rare in young patients. We report the first case of a follicular variant of peripheral T cell lymphoma not otherwise specified in an 11-year-old boy, who presented with a large mediastinal mass. Microscopic examination of the mediastinal biopsy revealed nodular infiltration of medium- to large-sized atypical lymphocytes. Immunohistochemistry showed expression of follicular helper T cell markers (CD10, PD1, CXCL13, and BCL6) in tumor T cells. Epstein-Barr virus (EBV) was not detected by an in situ hybridization assay for EBV-encoded RNA. Interestingly, fluorescence in situ hybridization detected the presence in the tumor cells of the t(5;9)(q33;q22) translocation, involving ITK and SYK rearrangement. T cell clonality was detected by multiplex PCR analysis of TRG and TRD gene rearrangements. After 4 cycles of systemic chemotherapy, the patient was in complete remission. Although this entity is very rare, our observations show that lymphomas arising from T follicular helper cells may occur in children and that this should be distinguished from other lymphomas, such T-lymphoblastic lymphomas, which require a specific therapeutic approach.
authors.affiliation: Laboratoire d'Anatomie Pathologique Institut Universitaire du Cancer Toulouse Oncopole, 31100, Toulouse, France.
authors.forename: Audrey
authors.initials: A
authors.lastname: Delas
authors.forename: Philippe
authors.initials: P
authors.lastname: Gaulard
authors.forename: Geneviève
authors.initials: G
authors.lastname: Plat
authors.forename: Pierre
authors.initials: P
authors.lastname: Brousset
authors.forename: Camille
authors.initials: C
authors.lastname: Laurent
mesh_terms: D001706:Biopsy; D002648:Child; D015329:Gene Rearrangement, T-Lymphocyte / Q000235:genetics; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000235:genetics; D016411:Lymphoma, T-Cell, Peripheral / Q000175:diagnosis* / Q000235:genetics / Q000473:pathology*; D008297:Male; D008479:Mediastinal Neoplasms / Q000175:diagnosis* / Q000235:genetics / Q000473:pathology*; D010641:Phenotype; D011505:Protein-Tyrosine Kinases / Q000235:genetics; D000072377:Syk Kinase; D006377:T-Lymphocytes, Helper-Inducer / Q000473:pathology
chemical_list: D047908:Intracellular Signaling Peptides and Proteins; D011505:Protein-Tyrosine Kinases; C000606896:SYK protein, human; D000072377:Syk Kinase; C080813:emt protein-tyrosine kinase