Malignant lymphoma of mucosa‐associated lymphoid tissue

TLDR

Lymphomas arising in mucosa‑associated lymphoid tissue (MALT) include gastrointestinal, salivary gland, lung, and thyroid tumors, mostly B‑cell but also T‑cell variants, which tend to remain localized yet T‑cell types have poor prognosis and are difficult to classify with standard non‑Hodgkin lymphoma schemes. The study aims to review the morphology of MALT lymphomas, present recent immunohistochemical and DNA‑analysis findings, and discuss their biological behavior to illuminate mucosal immune mechanisms. The authors reviewed morphological characteristics and applied immunohistochemical staining and DNA analysis to characterize MALT lymphomas. The review highlights that MALT lymphomas exhibit distinct morphological patterns, immunophenotypes, and genetic alterations, underscoring their varied biological behavior and the role of mucosal immunity.

Abstract

Lymphomas of the gastrointestinal tract, salivary glands, lung and thyroid are grouped together as tumours arising in mucosa‐associated lymphoid tissue. The great majority of them are of B‐cell origin but distinctive T‐cell lymphomas are also recognized in the gastrointestinal tract. These lymphomas tend to remain localized for prolonged periods but, whereas the B‐cell group respond favourably to local therapy, the T‐cell group are associated with severe morbidity and their overall prognosis is extremely poor. Accepted histological classifications of non‐Hodgkin's lymphomas are difficult to apply to these tumours. In this paper their morphological features are reviewed; recent findings based on immunohistochemistry and DNA analysis are presented; and the biological behaviour of these tumours is discussed insofar as they offer insight into mucosal immunological mechanisms.