Endoscopy is key to diagnosing MALT lymphoma, with multiple biopsies of the visible lesions required, as well as samples of macroscopically normal tissue, termed gastric mapping.

Histologically, there is expansion of the marginal zone compartment with development of sheets of neoplastic small lymphoid cells.

A characteristic feature of MALT lymphoma is the presence of neoplastic cells within epithelial structures with associated destruction of the glandular architecture to form lymphoepithelial lesions.

[2] MALT lymphoma may be difficult to distinguish from reactive infiltrates, and in some cases, multiple endoscopies are required before a confident diagnosis is reached.

The Wotherspoon score, which grades the presence of histological features associated with MALT lymphoma, is useful in expressing confidence in diagnosis at presentation.

As proton-pump inhibition can suppress infection, any treatment with this class of drug should be ceased 2 weeks prior to biopsy retrieval.

[9][10] A t(11;18)(q21;q21) chromosomal translocation, giving rise to an API2-MLT fusion gene,[11] is predictive of poor response to eradication therapy.

Chemotherapy is reserved for those uncommon patients with disseminated disease at presentation or lack of response to local treatment.

[19] The purine nucleoside analogs fludarabine and cladribine also demonstrate activity,[20] the latter conferring a CR rate of 84% (100% in those with gastric primaries) in a small study.