Extranodal marginal zone lymphoma (ENMZL), a subtype of non-Hodgkin lymphoma, is an indolent mature postgerminal center low-grade B-cell lymphoma that involves mucosa-associated lymphoid tissues (MALT lymphoma) (most commonly in the stomach as well as ocular adnexa, salivary gland, skin, lung, or small intestine). Generally, ENMZL remains localized but does have potential to systematically spread and transform into an aggressive B-cell lymphoma.

ENMZL is relatively uncommon and occurs mostly in adults with a median age at diagnosis of 66 years. It makes up 5%-10% of non-Hodgkin lymphomas.

ENMZL is said to evolve as a result of chronic immune stimulation. There are several well-known infection associations: Helicobacter pylori in gastric cases, Chlamydia psittaci infection in ocular adnexal cases, Campylobacter jejuni in small intestinal disease, Borrelia burgdorferi in cutaneous disease, and Achromobacter xylosoxidans in pulmonary ENMZL. Autoimmune diseases are another form of chronic immune stimulation that have been associated with ENMZL (ie, Sjögren syndrome, Hashimoto thyroiditis). Treatment of H pylori has been known to eradicate lymphoma in some cases.

Patients may present with symptoms of gastroesophageal reflux disease, abdominal pain, weight loss, or a slowly growing mass, or some patients may be asymptomatic. Sometimes a monoclonal gammopathy may be present, which is associated with plasmacytic differentiation of the neoplastic cells.

Related topics: Cutaneous B-cell lymphoma, Nodal marginal zone lymphoma, Splenic marginal zone lymphoma