Marginal zone lymphomas (MZL) are a heterogeneous subtype of indolent B-non-Hodgkin lymphomas that includes distinct entities:
- Extranodal mucosa-associated lymphoid tissue lymphoma arises in a variety of tissue but primarily in the stomach. They are usually localised and often associated with chronic antigenic stimulation by microbial pathogens. Eradication of the pathogen is a major part of the first-line therapy. The prognosis is excellent in early stages. In advanced stages, observation, anti-CD20 antibodies and/or cytostatic drugs are therapeutical approaches.
- Nodal MZL is usually confined in lymph nodes, bone marrow and peripheral blood. The prognosis is somewhat worse in this entity. Current recommendations suggest that they should be managed as follicular lymphomas.
- Splenic MZL is a unique entity involving the spleen, bone marrow and blood. Hepatitis infection should be eradicated before considering treatment. These lymphomas have an indolent behaviour, and only symptomatic patients should be treated by splenectomy and/or anti-CD20 antibodies.
- Two novel entities are described, non-chronic lymphocytic leukaemia monoclonal B-cell lymphocytosis, probably closely related to splenic MZL lymphoma, and a less well-defined provisional entity involving primarily the spleen called splenic B-cell lymphoma/leukaemia, unclassifiable, including splenic diffuse red pulp lymphoma and hairy-cell leukaemia variant.
This review will discuss separately the diagnosis, work-up and treatment of extranodal mucosa-associated lymphoid tissue lymphoma, nodal MZL and splenic MZL. These guidelines include the recently published ESMO consensus conference on malignant lymphoma.1–3
(BELG J HEMATOL 2019;10(4):153–64)