Comparison of PEL- and MCD-associated plasmablastic lymphoma
| . | PEL . | Plasmablastic5-150lymphoma . |
|---|---|---|
| Site | Body cavity, extranodal | Lymph nodes, spleen |
| Morphology | Immunoblasts | Plasmablasts |
| KSHV | Positive | Positive |
| EBV | Positive in majority | Negative |
| Cytoplasmic Ig expression | Absent | High level of IgM |
| Ig light chain | Monotypic κ or λ mRNA | Monotypic λ Ig |
| CD30 | Positive | Weakly positive |
| B-cell antigens | Absent | Weak or absent |
| Mutation inIg genes | Hypermutated in majority | Absent |
| Cellular origin | Germinal center or post-germinal center B cells | Naı̈ve IgMλ-expressing B cells |
| . | PEL . | Plasmablastic5-150lymphoma . |
|---|---|---|
| Site | Body cavity, extranodal | Lymph nodes, spleen |
| Morphology | Immunoblasts | Plasmablasts |
| KSHV | Positive | Positive |
| EBV | Positive in majority | Negative |
| Cytoplasmic Ig expression | Absent | High level of IgM |
| Ig light chain | Monotypic κ or λ mRNA | Monotypic λ Ig |
| CD30 | Positive | Weakly positive |
| B-cell antigens | Absent | Weak or absent |
| Mutation inIg genes | Hypermutated in majority | Absent |
| Cellular origin | Germinal center or post-germinal center B cells | Naı̈ve IgMλ-expressing B cells |
The term plasmablast is used to connote a medium-sized cell with a moderate amount of amphophilic cytoplasm and a large vesicular nucleus containing up to 3 prominent nucleoli. In contrast to an immunoblast, the cytoplasm contains abundant Ig.