Marginal zone lymphomas: management of nodal, splenic, and MALT NHL.
Marginal zone lymphomas are indolent B-cell lymphomas that originate from the marginal zone of B-cell follicles. For several subtypes, the initiation of disease appears to be a consequence of chronic infection and/ or inflammation. While the initial lymphoid hyperplasia is driven by physiologic antigenic stimulation, additional oncogenic events, such as chromosomal translocations leading to constitutive activation of signaling pathways, occur during the progression of disease that ultimately result in antigen-independent lymphoproliferation. Despite having a common origin in the marginal zone of the B-cell follicle, there are distinct clinical and molecular characteristics of marginal zone lymphomas originating at different anatomic sites. As such, marginal zone-derived lymphomas are currently categorized by the World Health Organization (WHO) into those originating in the spleen (splenic marginal zone lymphoma), extranodal mucosa-associated lymphoid tissue (MALT lymphoma), or lymph node (nodal marginal zone lymphoma).