Table 2.
Phenotyping splenic marginal zone lymphoma and its differential diagnosis.
| Antibody | Immunoreactivity | Staining Pattern | Description | Also Detected in |
|---|---|---|---|---|
| Annexin A1 | No | Cell membrane | HCL, specific marker | HCL |
| BRAF | No | Nuclear | None | HCL |
| Cyclin D1 | No | Nuclear | None | MCL, PCM |
| BCL2 | Yes | Cell membrane and cytoplasm | (+) in neoplastic B- cells, (−) in residual germinal centers | Most other small B-cell lymphomas |
| BCL6 | No | Nuclear | (−) in neoplastic cells, (+) in residual germinal centers, may be (+) in transformed SMZL | BL, DLBCL, FL |
| CD5 | Yes | Cell membrane | (+) in ~20% of cases, often dim reactivity | CLL/SLL, MCL |
| CD10 | No | Cell membrane | (+) only in residual germinal centers | BL, DLBCL, FL |
| CD11c | Yes | Cell membrane | Flow marker, (+) in 50% of cases | HCL |
| CD20 | Yes | Cell membrane | Pan-B-cell marker, neoplastic B-cells (+) | Most other B-cell lymphomas |
| CD21 | Yes | Dendritic pattern | (+) in follicular dendritic cell meshworks | FL |
| CD23 | No | Dendritic pattern | (+) in follicular dendritic cell meshworks | CLL/SLL, FL |
| CD25 | Yes | Cell membrane | Flow and immunohistochemistry marker, (+) in subset of cases | HCL |
| CD103 | Yes | Cell membrane | Flow and immunohistochemistry marker, (+) in small % of cases | HCL |
| DBA44 | Yes | Cell membrane | (+) in subset of cases | HCL |
| IgD | Yes | Cell membrane | (+) in subset of cases | Reactive mantle zones |
| IgM | Yes | Cell membrane | (+), most cases | |
| Ki-67 | Yes | Nuclear | Positive staining in both the germinal center and marginal zone which has been described as the so-called targetoid pattern. | Differing proliferation index in each lymphoma |
Abbreviations: BL = Burkitt lymphoma, CLL/SLL = chronic lymphocytic leukemia/small lymphocytic lymphoma, DLBCL = diffuse large B-cell lymphoma, FL = follicular lymphoma, HCL = hairy cell leukemia, MCL = mantle cell lymphoma, PCM = plasma cell myeloma.