Lung
Lymphohistiocytic tumors
MALT lymphoma
Author: Deepali Jain, M.D.
Last author update: 1 September 2012
Last staff update: 18 March 2021
Copyright: 2003-2023, PathologyOutlines.com, Inc.
PubMed Search: MALT lymphoma lung
Table of Contents
Definition / general | Terminology | Etiology | Case reports | Treatment | Gross description | Gross images | Microscopic (histologic) description | Microscopic (histologic) images | Positive stains | Negative stains | Differential diagnosisCite this page: Jain D. MALT lymphoma. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/lungtumormalt.html. Accessed March 26th, 2023.
Definition / general
- Lymphoma of Mucosal Associated Lymphoid Tissue - a type of marginal zone lymphoma
- 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
Terminology
- BALT (lymphoma of Bronchus Associated Lymphoid Tissue) is a rare, low grade, primary pulmonary MALT lymphoma
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
- 41 year old woman with multiple lung nodules, negative flow cytometry but clonal IgH gene rearrangement (Arch Pathol Lab Med 2003;127:115)
Treatment
- Local resection for limited disease, chemoradiotherapy for advanced disease
Gross description
- Solitary discrete mass, occasionally multiple nodules
Gross images
Contributed by anonymous
Discrete tan mass
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
Contributed by anonymous
Lymphoepithelial lesion
Monotonous population
of small-intermediate cells
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)
