Primary Extranodal Follicular Lymphoma: A Retrospective Survey of the International Extranodal Lymphoma Study Group (IELSG)

The characteristics at diagnosis and clinical course of primary extranodal follicular lymphoma (EFL) have not been extensively described. The International Extranodal Lymphoma Study Group (IELSG) conducted an international retrospective survey aimed to describe the clinical features at diagnosis and the outcomes of FL cases with a clinically dominant extranodal component. The dataset included 605 pathologically reviewed cases from 19 different countries, and their outcomes were compared to those of nodal follicular lymphomas. The two most common presentation sites for EFL were the skin (n = 334) and the gastrointestinal tract (n = 72), with 22 cases having primary duodenal localization. These subsets exhibited unique features at diagnosis and significantly different overall survival (OS) patterns. After a median follow-up of 5.5 years, primary cutaneous lymphomas showed a superior outcome [10-year OS: 89% (95% CI, 83%-93%)], while primary gastrointestinal lymphomas had an intermediate outcome [10-year OS: 79% (95% CI, 59%-90%)]. Among the gastrointestinal lymphomas, primary duodenal lymphomas tended toward the best outcome [10-year OS: 95% (95% CI, 69%-99%)]. Other primary extranodal sites had inferior outcomes [10-year OS: 59% (95% CI, 48%-68%)], similar to primary nodal lymphomas [10-year OS: 57% (95% CI, 49%-64%)]. These findings support the identification of specific primary FL localizations as distinct entities with particular clinical and biological characteristics.

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Publication Details

Journal
Hematological Oncology
Published
2025-06-22
DOI
https://doi.org/10.1002/hon.70111
Primary Topic
Lymphoma Diagnosis and Treatment
Type
article
Field-Weighted Citation Impact
0.00

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article

Primary Extranodal Follicular Lymphoma: A Retrospective Survey of the International Extranodal Lymphoma Study Group (IELSG)

Luca Mazzucchelli, Silvia Montoto, Armando López‐Guillermo, Richard Tsang et al.
Hematological Oncology
Lymphoma Diagnosis and Treatment
article

Primary Extranodal Follicular Lymphoma: A Retrospective Survey of the International Extranodal Lymphoma Study Group (IELSG)

Luca Mazzucchelli, Silvia Montoto, Armando López‐Guillermo, Richard Tsang, Barbara Pro, Vít Procházka, Luciano Cascione, Mirco Ponzoni, Stefano Luminari, Maria Cristina Pirosa, Andrea Janíková, Annarita Conconi, Francesca Maria Rossi, Carlo Visco, Gianluca Gaïdano, Anastasios Stathis, Chiara Lobetti‐Bodoni, Michael Mian, Barbara Vannata, David Belada, Gloria Margiotta Casaluci, Gerassimos A. Pangalis, María Elena Cabrera, Ana Florencia Ramírez‐Ibarguen, Andrés J.M. Ferreri, Igor Aurer, Marek Trněný, Samuel Hricko, Emanuele Zucca, Massimo Federico, G.B. Ryan, Grzegorz Nowakowsky
article en

Abstract

The characteristics at diagnosis and clinical course of primary extranodal follicular lymphoma (EFL) have not been extensively described. The International Extranodal Lymphoma Study Group (IELSG) conducted an international retrospective survey aimed to describe the clinical features at diagnosis and the outcomes of FL cases with a clinically dominant extranodal component. The dataset included 605 pathologically reviewed cases from 19 different countries, and their outcomes were compared to those of nodal follicular lymphomas. The two most common presentation sites for EFL were the skin (n = 334) and the gastrointestinal tract (n = 72), with 22 cases having primary duodenal localization. These subsets exhibited unique features at diagnosis and significantly different overall survival (OS) patterns. After a median follow-up of 5.5 years, primary cutaneous lymphomas showed a superior outcome [10-year OS: 89% (95% CI, 83%-93%)], while primary gastrointestinal lymphomas had an intermediate outcome [10-year OS: 79% (95% CI, 59%-90%)]. Among the gastrointestinal lymphomas, primary duodenal lymphomas tended toward the best outcome [10-year OS: 95% (95% CI, 69%-99%)]. Other primary extranodal sites had inferior outcomes [10-year OS: 59% (95% CI, 48%-68%)], similar to primary nodal lymphomas [10-year OS: 57% (95% CI, 49%-64%)]. These findings support the identification of specific primary FL localizations as distinct entities with particular clinical and biological characteristics.

Hematological OncologyVol. 43(4)
University of Verona (IT), University of Modena and Reggio Emilia (IT), Università degli Studi del Piemonte Orientale “Amedeo Avogadro” (IT), SIB Swiss Institute of Bioinformatics (CH), St Bartholomew's Hospital (GB), University Health Network (CA), Mayo Clinic (US), University Hospital Centre Zagreb (HR), Vita-Salute San Raffaele University (IT), Charles University (CZ), Peter MacCallum Cancer Centre (AU), CTO Hospital (IT), Princess Margaret Cancer Centre (CA), Azienda Sanitaria Unità Locale di Reggio Emilia (IT), Ospedale degli Infermi (IT), Ente Ospedaliero Cantonale (CH), Hospital del Salvador (CL), Institute of Oncology Research (CH), University Hospital Brno (CZ), University Hospital Olomouc (CZ), Hospital Clínic de Barcelona (ES), Azienda Ospedaliero Universitaria Maggiore della Carita (IT), IRCCS Ospedale San Raffaele (IT), Athens Medical Center (GR), University Hospital Hradec Králové (CZ), Mayo Clinic in Florida (US), Northwestern Medicine (US), Hospital Universitari de Vic (ES), Istituto Cantonale di Patologia (CH), Ospedale degli Infermi (IT), Istituti di Ricovero e Cura a Carattere Scientifico (IT), Instituto Nacional de Cancerología (MX), General University Hospital in Prague (CZ), Università della Svizzera italiana (CH), University of Chile (CL)
Swiss Cancer Research Foundation, Staatssekretariat für Bildung, Forschung und Innovation
Partnerships for the goals
Openalex Percentile: Top 78%
Lymphoma Diagnosis and Treatment
DOIOpen Access PDFOpenAlex
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