Marginal Zone Lymphoma

Overview

Lymphoma is the most common blood cancer. The two main forms of lymphoma are Hodgkin lymphoma (HL) and non-Hodgkin lymphoma (NHL). Lymphoma occurs when lymphocytes, a type of white blood cell, grow abnormally. The body has two main types of lymphocytes that can develop into lymphomas: B-lymphocytes (B-cells) and T-lymphocytes (T-cells). Cancerous lymphocytes can travel to many parts of the body, including the lymph nodes, spleen, bone marrow, blood or other organs, and can accumulate to form tumors.

Marginal zone lymphoma is a group of indolent (slow-growing) B-cell lymphomas, which account for approximately 12 percent of all B-cell lymphomas. The median age for diagnosis is 65.

Subtypes

There are three types of marginal zone lymphoma:

Extranodal marginal zone lymphoma of mucosa-associated lymphatic tissue (MALT) is the most common form of marginal zone lymphoma. It occurs outside the lymph nodes, such as the stomach, small intestine, salivary gland, thyroid, eyes and lungs. MALT is divided into two categories: gastric MALT, which develops in the stomach, and non-gastric MALT, which develops outside of the stomach. This form of lymphoma makes up approximately 9 percent of all B-cell lymphomas.

In many cases of MALT lymphoma, there is a previous medical history of inflammation or autoimmune disorders. For example, Helicobacter pylori (H. pylori), a microbial pathogen linked to chronic gastritis, has been associated with a significant portion of gastric MALT patients.

Nodal marginal zone lymphoma (sometimes called monocytoid B-cell lymphoma) occurs within the lymph nodes and makes up approximately 2 percent of all B-cell lymphomas.

Splenic marginal zone lymphoma occurs mostly in the spleen and blood. It has been associated with Hepatitis C. This form of lymphoma makes up approximately 1 percent of all B-cell lymphomas. 

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Absence of TCL1A expression is a useful diagnostic feature in splenic marginal zone lymphoma.

Oct 2012

Munari E, Rinaldi M, Ambrosetti A, Bonifacio M, Bonalumi A, Chilosi M, Zamò A.

Source

Department of Pathology and Diagnostics, Section of Anatomic Pathology, University of Verona, P.le Scuro 10, 37134, Verona, Italy.

Abstract

Splenic marginal zone lymphoma (SMZL) is a low-grade lymphoma showing a rather nonspecific immunophenotype. Gene expression profiling studies suggested that TCL1A could be a marker of SMZL, but reported data are conflicting. We evaluated TCL1A expression in a series of spleen and bone marrow samples involved by SMZL and correlated the findings with other immunophenotypical, morphological, and clinical data. In addition, we evaluated the expression of TCL1A in a series of spleens and lymph nodes involved by lymphomas that might mimic SMZL (13 nodal marginal zone lymphomas (NMZL), 39 follicular lymphomas (FL), 30 B-cell chronic lymphocytic leukemias (B-CLL), 31 mantle cell lymphomas (MCL), 1 lymphoplasmacytic lymphoma) and 15 bone marrow specimens involving hairy cell leukemia (HCL). TCL1A staining was negative in 24/31 cases of SMZL (77 %); 27/31 MCL and all B-CLL were positive for TCL1A; 32/34 cases of nodal FL (96 %) and all five splenic FL were positive for TCL1A, although at a lower intensity. Eight of 13 NMZL were positive for TCL1A, often showing a heterogeneous staining pattern. All HCL samples were strongly positive for TCL1A. No correlation was found between the pattern of splenic infiltration, TCL1A expression, and the clinical course. TCL1A-positive SMZL showed a higher rate of DBA44 staining compared to the negative ones, and this difference was statistically significant (Fisher test, single-tailed, p = 0.0397). Our data support the use of TCL1A in the panel of diagnostic markers used in the differential diagnosis of splenic low-grade B-cell lymphoma; a possible prognostic value, however, needs a larger series to be established.

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