title: Clonally related follicular lymphomas and Langerhans cell neoplasms: expanding the spectrum of transdifferentiation.
abstract: The traditional model of hematopoiesis is based on unidirectional maturation of hematopoietic precursors into lineage-committed cells. However, recent studies indicate that mature B lymphocytes may demonstrate significant lineage plasticity. We and others have reported transdifferentiation of follicular lymphomas (FLs) into clonally related histiocytic/dendritic cell neoplasms. Here, we describe 2 patients with FL who developed clonally related Langerhans cell neoplasms. The first was a 52-year-old man diagnosed with FL, grade 1. He received immunochemotherapy and had stable disease for 8 years. He then developed increasing lymphadenopathy, and lymph node biopsy showed Langerhans cell sarcoma with no evidence of FL. The second patient was a 77-year-old woman who presented with lymphadenopathy, an abdominal mass, and pulmonary nodules. Lymph node biopsy showed both Langerhans cell histiocytosis and minimal involvement by FL, grade 1. In each case, a combination of immunoglobulin gene rearrangement and fluorescence in situ hybridization studies provided evidence to support a clonal relationship between the FL and Langerhans cell neoplasm. These cases provide striking examples of neoplastic transdifferentiation and expand the spectrum of lesions clonally identical to otherwise typical FL. Awareness of this phenomenon may aid in diagnosis when histologically dissimilar tumors arise synchronously or metachronously in patients with lymphoma.
authors.affiliation: Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN 55905, USA.
authors.forename: Dava S
authors.initials: DS
authors.lastname: West
authors.forename: Ahmet
authors.initials: A
authors.lastname: Dogan
authors.forename: Patrick S
authors.initials: PS
authors.lastname: Quint
authors.forename: Melissa L
authors.initials: ML
authors.lastname: Tricker-Klar
authors.forename: Julie C
authors.initials: JC
authors.lastname: Porcher
authors.forename: Rhett P
authors.initials: RP
authors.lastname: Ketterling
authors.forename: Mark E
authors.initials: ME
authors.lastname: Law
authors.forename: Ellen D
authors.initials: ED
authors.lastname: McPhail
authors.forename: David S
authors.initials: DS
authors.lastname: Viswanatha
authors.forename: Paul J
authors.initials: PJ
authors.lastname: Kurtin
authors.forename: Linda N
authors.initials: LN
authors.lastname: Dao
authors.forename: Ryan D
authors.initials: RD
authors.lastname: Ritzer
authors.forename: Grzegorz S
authors.initials: GS
authors.lastname: Nowakowski
authors.forename: Andrew L
authors.initials: AL
authors.lastname: Feldman
mesh_terms: D000368:Aged; D054338:Cell Transdifferentiation; D002999:Clone Cells; D005260:Female; D005434:Flow Cytometry; D015321:Gene Rearrangement; D006801:Humans; D007143:Immunoglobulin Heavy Chains / Q000235:genetics; D016130:Immunophenotyping; D017404:In Situ Hybridization, Fluorescence; D054752:Langerhans Cell Sarcoma / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D007801:Langerhans Cells / Q000378:metabolism / Q000473:pathology*; D008224:Lymphoma, Follicular / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D016609:Neoplasms, Second Primary / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D048493:Proto-Oncogene Proteins B-raf / Q000235:genetics / Q000378:metabolism
chemical_list: D007143:Immunoglobulin Heavy Chains; C482119:BRAF protein, human; D048493:Proto-Oncogene Proteins B-raf