Lung tumor
Lymphoma and lymphoid infiltrates
MALT lymphoma

Author: Deepali Jain, M.D. (see Authors page)

Revised: 3 January 2017, last major update September 2012

Copyright: (c) 2003-2017, PathologyOutlines.com, Inc.

PubMed Search: malt lymphoma lung
Cite this page: MALT lymphoma. PathologyOutlines.com website. http://pathologyoutlines.com/topic/lungtumormalt.html. Accessed May 23rd, 2017.
Definition / general
  • Lymphoma of Mucosal Associated Lymphoid Tissue - a type of marginal zone lymphoma
  • See also lymphoma of bronchial associated lymphoid tissue (BALT)
  • Called pseudolymphoma in older literature
  • In adults, lung MALT is usually low grade, median age 68 years (range 34 - 88), often associated with autoimmune disorders, monoclonal gammopathies, hepatitis C, Helicobacter pylori gastritis
  • 44% involve mediastinal nodes
  • Usually indolent with excellent prognosis (Am J Surg Pathol 2001;25:997)
  • May recur locally, rarely transforms, few die of disease
  • 20% have monoclonal gammopathy, 30% have pleural effusions
  • Flow cytometry of tumor cells is useful in phenotyping; may even be helpful on peripheral blood
Etiology
  • In pediatric HIV patients with lymphoid interstitial pneumonitis, chemokines and cytokines may recruit inflammatory cells, either representing an early stage of MALT or providing a microenvironment for the evolution of a monoclonal B-cell population (Mod Pathol 2001;14:929)
Case reports
Treatment
  • Local resection for limited disease, chemoradiotherapy for advanced disease
Gross description
  • Solitary discrete mass, occasionally multiple nodules
Gross images

Images hosted on PathOut server:

Discrete tan mass (contributed by anonymous)

Microscopic (histologic) description
  • Nodular pattern of monotonous, mature lymphocytes with germinal centers that infiltrate overlying epithelium (lymphoepithelial lesions) and around vessels, pleura and alveolar septa
  • Cells may be monocytoid or resemble centrocytes
  • Also reactive plasma cells, variable fibrosis and epithelioid granulomas
  • Also colonization of germinal centers by tumor cells
  • Rarely granulomatous vasculitis
Microscopic (histologic) images

Images hosted on PathOut server:

Lymphoepithelial lesion (contributed by anonymous)

Monotonous population
of small-intermediate cells
(contributed by anonymous)



Images hosted on other servers:

Figure 1: CT with multiple pulmonary nodules
2A: lymphocytic proliferations with some germinal centers
2B: lymphoepithelial lesions associated with bronchial mucosa

Positive stains
Negative stains
Differential diagnosis
  • Benign lymphoid aggregates / reactive disorder: architecture is preserved, associated with immunosuppression and collagen vascular disease; not monoclonal by flow cytometry or PCR (Am J Surg Pathol 2002;26:76)