Nodal marginal zone lymphoma designates a group of lymphomas, possibly heterogeneous, that appear to originate in the marginal zone that surrounds the mantle zone of lymph node follicles [1-3]. This lymphoma was previously known as monocytoid B-cell lymphoma. The clinical presentation is with lymphadenopathy. Some cases may be closely related to extranodal marginal zone lymphoma and others to splenic marginal zone lymphoma. An association with hepatitis C has been observed in a minority of patients .
By definition, disease is mainly nodal but otherwise disease characteristics are not well defined. The disease tends to be indolent and most patients present with advanced stage disease.
Haematological and pathological features
Bone marrow and peripheral blood involvement are rare. The lymphoma cells are small to medium sized with a variable amount of cytoplasm, sometimes scanty and sometimes pale and abundant (monocytoid B cell). The nucleus is irregular.
Lymphoma cells occupy the interfollicular region of lymph nodes or the marginal zone of residual follicles or both (Figures 8.1 and 8.2). Monocytoid B cells may be prominent but in other patients cells more closely resemble small lymphocytes. Follicular colonization can occur. Bone marrow infiltration may be random focal, paratrabecular or nodular. Neoplastic cells may be small or medium sized and sometimes have irregular nuclei and abundant pale cytoplasm.
Section of lymph node biopsy from a patient with nodal marginal zone lymphoma, showing marginal zone infiltration. H&E, x 20 objective.
Section of lymph node biopsy from a patient with nodal marginal zone lymphoma, showing marginal zone infiltration, which is accentuated by immunohistochemistry for immunoglobulin D. Immunoperoxidase, x 20 objective.
Some patients have a serum paraprotein.
Lymphoma cells express weak monoclonal immunoglobulin and B-cell-associated antigens such as CD20, CD22, CD79a and CD79b. They do not usually express CD5, CD10, CD23, CD43, cyclin D1 or BCL6. CD11c is sometimes expressed.
Cytogenetic and molecular genetic abnormalities
Genetic abnormalities are not well characterized.
Diagnosis and differential diagnosis
The differential diagnosis includes (i) marginal zone/monocytoid B-cell hyperplasia, (ii) secondary nodal involvement by extranodal and splenic marginal zone lymphoma and (iii) other low-grade B-cell non-Hodgkin's lymphoma, particularly lymphoplasmacytic lymphoma.
This lymphoma is indolent but not curable.
Treatment is as for other low-grade lymphomas with there being no consensus as to the optimal agent .
A (2005). Modern histological classification of low grade ...