Lymphoplasmacytic Lymphoma
Differential Diagnosis
Small B Cell Lymphomas
- CD23 staining refers to lymphoid staining
- Follicular dendritic cells stain in many processes
- bcl1
- Blastic mantle cell lymphoma 100%
- Hairy cell leukemia 41%
- CD43 stains only 2% of splenic marginal zone lymphoma
| Lymphoplasmacytic Lymphoma / Immunocytoma |
SLL/CLL |
| Proliferation centers absent |
Proliferation centers frequent |
| Plasmacytoid differentiation marked |
Plasmacytoid differentiation variable |
| CD5 5% |
CD5 80% |
| CD23 0-30% on immunohistology but up to 60% weak positive on flow |
CD23 85% |
Plasmacytoid diffrentiation may be prominent in mantle cell lymphoma
- No useful distinguishing immunologic markers
- Marginal zone lymphomas are frequently plasmacytoid; this combined with the lack of a definitive marker can make this distinction difficult
- The distinction is sometimes suggested by the propensity to involve mucosal sites by extranodal marginal zone lymphoma
| Plasmacytoma / Myeloma |
Lymphoplasmacytic Lymphoma and Nodal, Extranodal and Splenic Marginal Zone Lymphomas |
| Plasma cells may be pleomorphic or plasmablastic |
Plasma cell component usually not markedly atypical |
| Uniform plasma cell morphology |
Plasma cells mixed with small lymphocytes |
| IgG or IgA M component most common |
IgM or IgG M component most common |
| CD20 often negative |
CD20 80% |
| Uniformly CD138 positive |
Scattered CD138 positive cells |
| Often CD56+, CD19-, CD45- |
CD56-, CD19+, CD45+ |
| Castleman disease |
Lymphoplasmacytic Lymphoma |
| Small burned out follicles |
Residual follicles infrequent |
| No intranuclear inclusions |
Intranuclear inclusions present |
| 30% of cases monotypic |
100% monotypic |
| IgG or IgA |
IgM or IgG |
Generally a problem only with small samples or LLI with an interfollicular pattern
