Follicular lymphoma (FL) is a neoplasm composed of follicle centre (germinal centre) B-cells (typically both centrocytes and centroblasts/large transformed cells), which usually has at least a partially follicular pattern. FL accounts for about 20% of all lymphomas, with the highest incidence in the USA and Western Europe. It affects predominantly adults, with a median age in the 6th decade and a male:female ratio of 1:1.7. FL rarely occurs in individuals under the age of 20 years.
Intestinal FL occurs mainly in the duodenum
Sato Y, Ichimura K, Tanaka T, Takata K, Morito T, Sato H, Kondo E, Yanai H, Ohara N, Oka T, Yoshino T (2008)
Duodenal follicular lymphomas share common characteristics with mucosa-associated lymphoid tissue lymphomas.
J Clin Pathol 61: 377-81
Schildhaus HU, Cavlar T, Binot E, BŁttner R, Wardelmann E, Merkelbach-Bruse S (2008)
and often presents as multiple small polyps. Most are localized to the intestine (primary intestinal FL) and some are an extension from primary nodal FLs. The immunophenotype and genetic features of primary intestinal FL are similar to those of nodal FLs. The localized form is associated with an excellent survival, even without treatment
Inflammatory fibroid polyps harbour mutations in the platelet-derived growth factor receptor alpha (PDGFRA) gene.
J Pathol 216: 176-82
Bosman FT, Carneiro F, Hruban RH, Theise ND (Eds.)
WHO Classification of Tumours of the Digestive System.
International Agency for Research on Cancer: Lyon 2010
Primary cutaneous follicle centre lymphomas
are separately classified
LeBoit PE, Burg G, Weedon D, Sarasin A (Eds.)
World Health Organization Classification of Tumours. Pathology and Genetics of Skin Tumours
IARC Press: Lyon 2005
Swerdlow SH, Campo E, Harris NL, Jaffe ES, Pileri SA, Stein H, Thiele J, Vardiman JW (Eds.)
WHO Classification of Tumours of Haematopoietic and Lymphoid Tissues
International Agency for Research on Cancer: Lyon 2008