title: Atypical Marginal Zone Hyperplasia Is a Mimic for Lymphoma in Pediatric Transplant Recipients: Report of Two Patients.
abstract: Atypical marginal zone hyperplasia (AMZH) of mucosa-associated lymphoid tissue (MALT) closely resembles lymphoma in that it shows expansion of the marginal zones with prominent intraepithelial B lymphocytes, is immunoglobulin light-chain restricted, and may show aberrant CD43 expression. However, unlike lymphoma, it does not show rearrangement of the immunoglobulin heavy chain gene (immunoglobulin H [IgH]) by polymerase chain reaction (PCR), and it behaves in a benign fashion. We identified AMZH in 2 pediatric solid organ transplant recipients who presented with adenotonsillar hypertrophy. To date, the patients have experienced a self-limited course in the absence of treatment or reduction of immunosuppression. Atypical marginal zone hyperplasia is a pitfall for posttransplant lymphoproliferative disorder and MALT lymphoma in the pediatric solid organ transplant population. In transplant patients with a lambda-restricted B-cell clone and marginal zone hyperplasia in native MALT sites, PCR for IgH and IgK gene rearrangement is essential to prevent misdiagnosis.
authors.affiliation: 1 Children's Healthcare of Atlanta, 1405 Clifton Road NE, Egleston Children's Hospital, Department of Pathology, First Floor, Tower One, Atlanta, GA 30322, USA.
authors.forename: Shelley A
authors.initials: SA
authors.lastname: Caltharp
authors.affiliation: 2 AFLAC Cancer and Blood Disorders Center and Emory University, 2015 Upper Gate Dr NE, 4th Floor, Atlanta, GA 30322, USA.
authors.forename: Muna
authors.initials: M
authors.lastname: Qayed
authors.affiliation: 1 Children's Healthcare of Atlanta, 1405 Clifton Road NE, Egleston Children's Hospital, Department of Pathology, First Floor, Tower One, Atlanta, GA 30322, USA.
authors.forename: Sunita I
authors.initials: SI
authors.lastname: Park
mesh_terms: D000234:Adenoids / Q000473:pathology*; D002648:Child; D002675:Child, Preschool; D003937:Diagnosis, Differential; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D006965:Hyperplasia / Q000276:immunology / Q000473:pathology; D016867:Immunocompromised Host; D016130:Immunophenotyping; D018442:Lymphoma, B-Cell, Marginal Zone / Q000175:diagnosis*; D016377:Organ Transplantation; D014066:Palatine Tonsil / Q000473:pathology*; D066027:Transplant Recipients
keywords: AMZH; PTLD; lymphoma mimic; posttransplant