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Uploaded: 2009-10-25, Updated: 2009-10-25

CLINICAL FEATURES

• Also called splenic lymphoma with villous lymphocytes.

• Most patients > 50 years old, M=F.

• Locations: spleen, splenic hilar lymph nodes, bone marrow and peripheral blood, maybe liver. Rarely extranodal or  peripheral lymph nodes.

• Autoimmune thrombocytopenia, anemia, PB villous lymphocytes.

• Cases with plasmacytic differentiation often present with monoclonal serum disorders and autoimmune disorders, including hemolytic anemia.

MICROSCOPIC FINDINGS

• Mixed mantle-zone and marginal-zone involvement: the tumor cells in the center are small and atypical with effacement of the normal mantle zone and colonization of the germinal center; the tumor cells in the peripheral (the marginal zone) are medium in size with pale cytoplasm and oval nucleus with dispersed chromatin;

• The tumor cells are centrocyte-like, monocytoid, lymphoplasmacytic, and < 20% immunoblasts;

• Always involves red pulp.

• PB: short polar villi.

IMMUNOPHENOTYPE

• CD20+, CD79a+, CD5-, CD23-, CD10-, CD43-, BCL1-, CD103-, annexin A1-, IgM+,  and IgD (dim),

DIFFERENTIAL DIAGNOSES

• CLL/SLL: less cytoplasm, more regular nuclei, more condensed chromatin, proliferative center, CD5+, CD23+.
• Mantle cell lymphoma: CD5+, BCL1+.
• Hair cell leukemia: red pulp involvement, blood lake, circumferential villi, CD103+, annexin A1+.

CYTOGENETIC STUDIES

• Del(7q31-32 ) of CDK6 gene may be associated with transformation.
• No t(11;18).

TREATMENT AND PROGNOSIS

• Indolent even with bone marrow involvement.
• Del(7q31-32 ) and unmutated IGHV gene are associated with unfavorable prognosis.

CASE STUDIES: HP-106

REFERENCES: WHO Classification of Tumours of Haematopoietic and Lymphoid Tissues, Fourth Edition. 2008.