A primary nodal lymphoma of small B lymphoid cells resembling those seen in extranodal marginal zone lymphoma but without the evidence of extranodal or splenic disease.
Synonyms: nodal monocytoid B-cell lymphoma, parafollicular B-cell lymphoma
A rare condition constituting 1.8% of lymphoid neoplasms.
Clinical features
The median age is 54, with a male predominance5. 90% of patients have no B symptoms5. There is involvement of peripheral lymph nodes and occasionally of bone marrow and blood. Patient commonly have a raised LDH, a raised serum b2-microglobulin and anaemia.
Histopathology
The marginal zones and interfollicular areas of lymph nodes are infiltrated by marginal zone B-cells, resembling centrocytes, monocytoid B-cells or small B-lymphocytes. Scattered blasts may be present but do not form sheets. There may be follicular colonization. Plasma cell differentiation may occur. Five architectural patterns have been described:
vaguely nodular: the nodules are small, lacking germinal centres or having atrophic germinal centres.
interfollicular: neoplastic cells are in the spaces between atrophic or hyperplastic follicles.
perifollicular: the neoplastic cells form enlarged marginal zones.
diffuse: the normal architecture is effaced but there is a nodular pattern.
inverse follicular: the cells in the centres are dark and those in the Interfollicular areas are paler.
A purely perisinusoidal pattern is very rare in NMZL and the biphasic pattern (a central zone of small lymphocytes surrounded by a peripheral zone of larger marginal zone cells) seen in splenic MZL does not occur.
Subtypes
Resembling nodal involvement by Malt lymphoma
Resembling splenic marginal-zone lymphoma
Composite lymphoma with concomitant follicular lymphoma; possibly these are follicular lymphomas with marginal zone differentiation.
Immunohistochemistry
|
SIg |
bcl-2 |
bcl-6 |
|||||||||
|
rare1, 0/215 |
very rare, 0/215 |
variable |
positive |
positive, 21/215 |
positive |
negative, 0/215 |
20-40% of cases, 1/205 |
positive |
16/215 |
9/215 |
.: fresh frozen tissue only
Cytogenetics
A characteristic cytogenetic abnormality has not been demonstrated5.
Differential diagnosis
Secondary nodal involvement by extranodal marginal zone lymphoma.
MALT lymphoma may show a marginal zone, perifollicular or inverse follicular pattern.
Distinction from lymphoplasmacytic lymphoma may be very difficult3. Major bone marrow involvement, a diffuse pattern in lymph nodes, the presence of mature plasma cells and an IgM gammopathy favours lymphoplasmacytic lymphoma4.
follicular colonization needs to be distinguished from progressive transformation of germinal centres2.
Prognosis
Median survival is over 5 years5, but with a high early relapse rate.
References
World Health Organization Classification of Tumours, Tumours of the haematopoietic and lymphoid tissues, IARC Press 2001.
Wotherspoon AC, Hasserjian RP. Immunophenotyping in the differential diagnosis of histologically low grade B cell lymphomas Current Diagnostic Pathology 2000;6:55-63.
2 Jones D. Dismantling the germinal center: comparing the processes of transformation, regression and fragmentation of the lymphoid follicle. Advances in Anatomic Pathology 2002;9:129-138.
This page last revised 30.1.2006.
©SMUHT/PW Bishop