Tiêu đề 9. Immunophenotypic work up of lymphomas and leukemia.pdf ✅

Immunophenotypic work-up of lymphomas & leukemias Dipti Anand, MD SkinPath Solutions Danand&skinpathsolutions.com Immunophenotype of B-cell lymphomas B-cells are CD20+ CD79a+ Bcl-2, bcl-6 and CD10- Germinal center markers Normal germinal centers are- bcl-2 –ve bcl-6+ CD10+ All B-cell lymphomas are bcl-2+, EXCEPT PRIMARY CUTANEOUS FOLLICLE CENTER (FOLLICULAR) LYMPHOMA WHICH IS BCL-2 NEGATIVE. CD5, CD23 and CD43 are T-cell markers which are aberrantly expressed in B-cell lymphomas. Immunophenotype of small B-cell lymphomas: 1. Follicular lymphoma- - bcl2+ bcl6+ CD10+ (shows t (14;18) (IgH;bcl2)) - Primary cutaneous follicular lymphoma is bcl2- bcl6+ CD10+ - CD5- CD23- - CD43- - Cyclin D1- - Strong positivity for both CD10 and bcl-2 should raise suspicion of secondary cutaneous involvement by nodal follicular lymphoma.
- Nodal follicular lymphomas show t(14;18) (IgH/bcl-2) 2. Chronic lymphocytic leukemia/Small lymphocytic lymphoma- - bcl2+ bcl6- CD10- - CD5+ CD23+ - CD43+ - Cyclin D1- - Poor prognosis is associated with cases expressing Zap70 and CD38, and those with deletions of 11q, 17p and 6q. - Cases with deletion 13q have a good prognosis 3. Mantle cell lymphoma- - bcl2+ bcl6- CD10- - CD5+ CD23- - CD43+ - Cyclin D1+ (t(11;14) (cyclinD1; IgH)) 4. Marginal zone lymphoma- - bcl2+ bcl6-CD10- - CD5- CD23- - CD43+ (~50%) - Cyclin D1- - In skin: t(14;18) (Igh; bcl2) and t(3;14) (FOX-P1; IgH) have been detected.
Diffuse Large B-cell Lymphoma/DLBCL - CD20+ CD79a+ - The diagnosis of this tumor is based on histology including cellular cytology and CD20 staining. - Further stains are usually done for prognostication of tumor - 2 Prognostic subtypes: - A. Germinal center B-cell phenotype (GCB)- GOOD PROGNOSIS - B. Activated B-cell phenotype (ABC)- BAD PROGNOSIS - Bcl-2 positivity in DLBCLs is associated with an adverse outcome (tumors with both bcl2 and c-myc translocations are call “Double Hit Lymphomas/DHLs”- poorer prognosis with extranodal disease) - A. Germinal center B-cell phenotype/GCB : - Bcl6+ CD10+ - Bcl6- CD10+ - Bcl6+ CD10- - For diagnosis of GCB-cell phenotype IRF4/MUM-1 has to be negative B. Activated B-cell phenotype (ABC phenotype): - IRF4/MUM-1 + - FOX-P1+ - CD138+ (syndecan-1+) (expressed in plasmablastic lymphomas) For ABC phenotype- MUM-1 has to be positive- - MUM-1+/bcl6+/CD10- - MUM-1+/bcl6-/CD10+ - MUM-1+/bcl6-/CD10- DLBCL, leg type is- bcl2-+ bcl-6+/- CD10-