Table 1.
Differential diagnosis of ALK+ LBCL and predominant staining patterns with several antibodies. This table summarizes the predominant staining patterns for these entities, with the understanding that exceptional cases have been reported. Typically, ALK+ LBCL demonstrates a postgerminal center phenotype and is negative for CD30. Rare cases expressing CD20, CD79a, or CD30 have been reported [5].
| ALK+ LBCL | ALK+ ALCL | DLBCL, NOS | Poorly differentiated carcinoma | Extramedullary plasmacytoma | |
|---|---|---|---|---|---|
| CD45 | + | + | + | − | |
| CD20 | − | − | + | − | |
| CD79a | − | + | + | ||
| MUM-1 | + | +/− | |||
| CD138 | + | − | − | +/− | + |
| ALK | + | + | − | − | − |
| CD30 | − | + | +/− | ||
| EMA | + | + | +/− | ||
| Keratin | +/− | +/− | |||
| EBER | − | − |