Mucosa-associated lymphoid tissue (MALT) is scattered along mucosal linings in the human body
and constitutes the most extensive component of human lymphoid tissue. These surfaces protect the body from an enormous quantity and variety of antigens. The tonsils, the Peyer patches within the small intestine, and the vermiform appendix are examples of MALT.
The nomenclature incorporates location; therefore, MALT is understood to include gut-associated lymphoid tissue (GALT), bronchial/tracheal-associated lymphoid tissue (BALT), nose-associated lymphoid tissue (NALT), and vulvovaginal-associated lymphoid tissue (VALT). Additional MALT exists within the accessory organs of the digestive tract, predominantly the parotid gland.
Chronic inflammation of MALT from infective or autoimmune disorders can lead to the development of extranodal marginal zone B-cell lymphomas, or MALTomas. The stomach is the most common location of MALTomas, while frequent nongastric sites include the following
Orbits and conjunctiva
Other gastrointestinal (GI) sites
MALTomas at different sites may involve different genetic lesions and may possibly have different natural histories.
Symptoms of MALTomas are nonspecific and are related to the organs involved. Most patients with MALTomas have no physical findings; lymphadenopathy is rare. Staging MALTomas can be challenging. Imaging studies are not helpful for visualizing normal MALT, but they may be useful in diagnosing and staging MALTomas. Endoscopy may be helpful. Bone marrow aspiration and biopsy findings can signal bone marrow involvement.
Treatment may include proton pump inhibitors (PPIs) and antibiotics for Helicobacter pylori infection, chemotherapy, radiotherapy, and, in some instances, surgical intervention.
For patient education resources, see the Blood and Lymphatic System Center, as well as Lymphoma.