Histopathology, immunohistochemistry, and genetics of BL, DLBCL, and B-UNC/BL/DLBCL
| . | BL . | DLBCL . | B-UNC/BL/DLBCL . |
|---|---|---|---|
| Histopathology | Medium-sized and highly monomorphic cells; multiple prominent nucleoli; basophilic cytoplasm; prominent cytoplasmic vacuoles. | Heterogeneous with larger cells; vesicular chromatin; multiple peripheral nucleoli; narrow rim of basophilic cytoplasm. | Intermediate to large neoplastic cells but monomorphic. |
| Interspersed benign histiocytes (classic “starry sky” appearance). | |||
| Ki67 index >95%. | Ki67 variable but usually <90%. | Ki67 intermediate between BL and DLBCL but high (∼90%). | |
| Immunohistochemistry | CD19, CD20, CD22, CD79a, CD10, BCL6, HLA-DR, and CD43 positive. | CD19, CD20, CD22, and CD79a positive. | CD19, CD20, CD33, CD79a positive. |
| BCL6 positive 60%-70% of time. | BCL6 variable but often positive. | ||
| BCL-2, CD5, TdT, and CD23 negative. | BCL2, CD10, CD5, CD30 and CD5 variable. | Uniformly CD10 positive. | |
| Commonly BCL2 positive. | |||
| Genetics | t(8;14) 80%; t(2;8) 15%; t(8;22) 5% | No single cytogenetic change that is typical. | “Double hit” cytogenetics with coincident translocations involving MYC and another locus, most often BCL2 30%-50%. |
| No translocation involving BCL6 or BCL2. | “Double hit” cytogenetics with coincident translocations involving MYC and another locus, most often BCL2 10%. |
| . | BL . | DLBCL . | B-UNC/BL/DLBCL . |
|---|---|---|---|
| Histopathology | Medium-sized and highly monomorphic cells; multiple prominent nucleoli; basophilic cytoplasm; prominent cytoplasmic vacuoles. | Heterogeneous with larger cells; vesicular chromatin; multiple peripheral nucleoli; narrow rim of basophilic cytoplasm. | Intermediate to large neoplastic cells but monomorphic. |
| Interspersed benign histiocytes (classic “starry sky” appearance). | |||
| Ki67 index >95%. | Ki67 variable but usually <90%. | Ki67 intermediate between BL and DLBCL but high (∼90%). | |
| Immunohistochemistry | CD19, CD20, CD22, CD79a, CD10, BCL6, HLA-DR, and CD43 positive. | CD19, CD20, CD22, and CD79a positive. | CD19, CD20, CD33, CD79a positive. |
| BCL6 positive 60%-70% of time. | BCL6 variable but often positive. | ||
| BCL-2, CD5, TdT, and CD23 negative. | BCL2, CD10, CD5, CD30 and CD5 variable. | Uniformly CD10 positive. | |
| Commonly BCL2 positive. | |||
| Genetics | t(8;14) 80%; t(2;8) 15%; t(8;22) 5% | No single cytogenetic change that is typical. | “Double hit” cytogenetics with coincident translocations involving MYC and another locus, most often BCL2 30%-50%. |
| No translocation involving BCL6 or BCL2. | “Double hit” cytogenetics with coincident translocations involving MYC and another locus, most often BCL2 10%. |
B-UNC/BL/DLBCL, B-cell lymphoma unclassifiable with features intermediate between BL and DLBCL.