Small Lymphocytic Lymphoma / Chronic Lymphocytic Leukemia
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
| Mantle Cell Lymphoma |
SLL/CLL |
| Irregular nuclear membranes |
Round nuclei |
| Residual germinal centers may be prominent |
Proliferation centers present |
| Expanded mantle zone around germinal centers variably present |
No mantle zone pattern |
| Scattered histiocytes |
Histiocytes not prominent |
| bcl1 85% |
bcl1 2% |
| CD23 2% |
CD23 85% |
| Blastic transformation |
Large cell transformation |
Some mantle cell lymphomas have been reported to have proliferation centers; these are better considered as SLL/CLL
| 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% |
| Nodal, Extranodal and Splenic Marginal Zone Lymphoma |
SLL/CLL |
| Enlarged marginal zone |
Diffuse effacement |
| Pale monocytoid cells |
Small round lymphocytes |
| May have residual germinal centers |
Proliferation centers frequent |
| CD23 8% |
CD23 85% |
| CD5 negative |
CD5 80% |
| CD43 35% (Splenic 2%) |
CD43 80% |
Both may involve the GI tract and other mucosal sites
| Follicular Lymphoma |
SLL/CLL |
| Distinct nodular pattern |
Vague proliferation centers |
| Nodules composed of cleaved cells |
Nodules composed of prolymphocytes and paraimmunoblasts |
| Interfollicular cleaved cells common |
Background sheets of regular small lymphocytes |
| CD23 0-38% |
CD23 85% |
| CD5 negative |
CD5 80% |
| CD43 7% |
CD43 80% |
| CD10 85% |
CD10 0% |
bcl2 stains over 90% of both
| Lymphocyte Predominant Hodgkin Lymphoma |
SLL/CLL |
| Wide age range |
Rare under 30 years |
| Limited number of large nodules |
Scattered small proliferation centers |
| Large atypical cells scattered in and around nodules |
Large cells confined to proliferation centers |
| CD23 negative |
CD23 85% |
| CD5 negative on B cells |
CD5 80% |
| CD43 negative on B cells |
CD43 80% |
| Large cells may be EMA positive |
EMA negative |
| Light chains polytypic or negative |
Light chains monotypic or negative |
| CD57+ small cells surrounding large cells |
No CD57 ringing pattern |
| Diffuse Large B Cell Lymphoma |
Paraimmunoblastic SLL/CLL |
| Nuclear shape variable |
Nuclei round, uniform |
| Nucleoli frequently multiple |
Nucleoli single |
| Cytoplasm may be basophilic |
Cytoplasm pale |
| Node capsule frequently destroyed |
Node capsule preserved even if overrun |
| CD5 rare |
CD5 80% |
| Burkitt Lymphoma |
Prolymphocytic SLL/CLL |
| Starry sky macrophages present |
Starry sky macrophages variable |
| Uniform population |
Admixed prolymphocytes and small cells |
| Cytoplasm amphophilic or basophilic |
Cytoplasm pale |
| Multiple nucleoli |
Single nucleolus |
| Ki67 nearly 100% |
Ki67 moderately high |
| CD23 negative |
CD23 85% |
| Translocation involving myc gene |
No myc translocation |
| Nodal Involvement by Prolymphocytic Leukemia |
Paraimmunoblastic SLL/CLL |
| Many circulating prolymphocytes |
<10% circulating prolymphocytes |
| Pure prolymphocytic infiltrate |
Predominantly paraimmunoblasts |
| Splenomegaly present |
Splenomegaly variable |
| Lymphadenopathy minimal |
Lymphadenopathy prominent |
| Chronic Inflammation |
SLL/CLL |
| Germinal centers may be present |
Proliferation centers indistinct |
| Mixed population |
Uniform small cells (except proliferation centers) |
| CD23 negative (follicular dendritic cells positive) |
CD23 85% positive on lymphocytes |
| No coexpression |
Coexpression of CD5 or CD43 75-100% |
| B and T zones |
Sheets of B cells |
| No light chain monotypia |
Light chain monotypia variably demonstrable |
| Clonal immunoglobulin rearrangements absent |
Clonal immunoglobulin rearrangements present |
| Capsular fibrosis infrequent |
Capsular fibrosis frequent |
| Plasmacytosis infrequent |
Plasmacytosis frequent |