Splenic marginal zone lymphoma (SMZL) is an indolent lymphoproliferative disease accounting for approximately 1% of all lymphomas.

Clinical synopsis

 marked splenomegaly
 circulating atypical 'villous lymphocytes'

Microscopical synopsis

 nodular infiltrate based on white pulp and red pulp
 white pulp:

• biphasic morphology: an inner zone of small lymphocytes and a peripheral (marginal) zone of larger lymphoid cells

 splenic lymph nodes and bone marrow: presence of a vaguely nodular infiltrate of similar nature.

Immunophenotype

 Tumor cells has a mature B-cell phenotype

• IgM+
• IgD+
• CD5-
• CD23-
• CD43-
• CD10-
• Bcl-6- (BCL6-)
• cyclin-D1-

Molecular biology

 Analysis of immunoglobulin heavy-chain gene variable regions suggest that some cases of SMZL arise form postfollicular B cells but others from naive B cells.

 abnormalities of a number of chromosomes

• 7q31-32 LOH

Differential diagnosis

 lymphoid hyperplasias
 other marginal zone lymphomas,
 mantle cell lymphoma
 follicular lymphoma
 B-CLL

See also

 cutaneous marginal zone B-cell lymphoma

References

 Taddesse-Heath L, Pittaluga S, Sorbara L, Bussey M, Raffeld M, Jaffe ES. Marginal zone B-cell lymphoma in children and young adults. Am J Surg Pathol. 2003 Apr;27(4):522-31. PMID: #12657939#

 Dogan A, Isaacson PG. Splenic marginal zone lymphoma. Semin Diagn Pathol. 2003 May;20(2):121-7. PMID: #12945935#