Table 3.
B cell non-Hodgkin lymphomas in the bone marrow
| Subtype | Cytology | Morphology | Immunophenotype | Diagnostic clue |
|---|---|---|---|---|
| SLL | Small and round nuclei | Focal but occasionally diffuse infiltration | CD20+, CD5+, CD23+, BCL2+, CD43+ | BCL2+ may cause misdiagnosis of FL |
| MCL | Highly variable nuclei: round, blastic or irregular | Focal, paratrabecular lesions | Cyclin D1+, CD20+, FMC7+, BCL2+, CD5- (10%) | Leukemic picture is common |
| FL | Dense chromatin with clefted nuclei | Strikingly paratrabecular pattern | CD20+, CD10+, BCL2+ | Discordancy between BM and LN lesions is common |
| SMZL | Various cell size spectrum | Mixed patterns | Variable, usually BCL2+, CIG+ | Leukemic picture is common |
| Other MZL | Variable | Mixed patterns | No distinctive feature, BCL2+ | Infiltrates may be occult |
| LPL | Plasmacytoid lymphocytes | Mixed patterns and common Dutcher bodies | CIG+, monoclonal plasma cells+ | Rouleaux formation is sometimes observed on PB smear |
| DLBCL and variants | Large lymphoid cells | Mixed patterns Rarely distinctive intravascular pattern | Clonal IGH, BCL2+/-, BCL6+ | Morphology may be discordant with EM sites |
| BL | Intermediate sized cells with basophilic cytoplasm | Leukemic pattern mixed with normal hematopoietic cells | CD43+, BCL2-, sometimes EBER+/- | |
| B-LL | Variable size | Leukemic interstitial pattern | Weak CD45+, CD34+, TdT+, CD10+ | Extent of BM involvement is less than 25% |
SLL, small lymphocytic lymphoma; FL, follicular lymphoma; MCL, mantle cell lymphoma; BM, bone marrow; LN, lymph node; SMZL, splenic marginal zone lymphoma; MZL, marginal zone lymphoma; LPL, lymphoplasmacytic lymphoma; PB, peripheral blood; DLBCL, diffuse large-cell B cell lymphoma; EM, extramedullary; BL, Burkitt lymphoma; B-LL, B-lymphoblastic lymphoma.