Version May 2024
| Entity | Histologic morphology | Immunophenotype | Genetic features/other |
| Chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL) | "Typical" CLL/SLL cells are small, mature-appearing lymphocytes with a dense nucleus; partially aggregated chromatin; no discernible nucleoli; and a narrow border of cytoplasm. Frequent disrupted cells (smudge cells) are often seen. A minority of cells may have a prolymphocytic morphology. Lymph node infiltrate typically comprised of small lymphocytes with condensed chromatin, round nuclei, and occasionally a small nucleolus. Larger lymphoid cells cluster in pseudofollicles, known as proliferation centers. These proliferation centers may create a vaguely nodular pattern of infiltration. | Always express CD5. Usually express CD23. Expression of CD20 and surface membrane immunoglobulin is dim. Do not overexpress cyclin D1 and do not express CD10. | Deletion 13q, trisomy 12, deletion 11q, and deletion 17p. TCR genes are not clonally rearranged. |
| Monoclonal B cell lymphocytosis | Absolute increase in the number of clonal B lymphocytes in the peripheral blood does not exceed 5000/microL [5 × 109/L]. | Immunophenotype identical to CLL. | Patients have no lymphadenopathy, organomegaly, cytopenias, or disease-related symptoms. |
| B cell prolymphocytic leukemia* | Prolymphocytes >55% of the neoplastic cells. Bone marrow has interstitial pattern of infiltration. Lymph nodes may show vague nodularity, but proliferation centers are absent. | Express bright surface membrane immunoglobulin and bright CD20, as well as other B cell antigens (CD19, CD22, CD79a, FMC7). Usually do not express CD5. | t(11;14) must be excluded. No associated paraproteinemia. |
| Mantle cell lymphoma | Can have a leukemic phase that mimics CLL/SLL morphologically with circulating small lymphocytes with irregular or cleaved nuclei. Lymph node infiltrate comprised of monomorphous small to medium-sized B lymphocytes with irregular nuclei. Sometimes encircles residual germinal centers (mantle zone pattern). No proliferation centers. | Coexpress CD20 and CD5, but do not express CD23. The vast majority stains strongly for cyclin D1 and has bright surface membrane immunoglobulin. | t(11;14) |
| Hairy cell leukemia (HCL) and hairy cell leukemia variant* | Typical hairy cells are mononuclear and one to two times the size of a small lymphocyte. The nuclei are often eccentric, lack prominent nucleoli, and have a reticular chromatin pattern. The cytoplasmic outline is indistinct with projections. Bone marrow biopsy demonstrates a "fried egg" appearance with an interstitial pattern of infiltration. Hairy cell variant has circulating tumor cells with morphology intermediate between hairy cells and prolymphocytes. In general, nucleoli are more prominent than in conventional HCL. | Unlike CLL/SLL, most cases of classic HCL express CD11c, CD103, CD123, and annexin A1. Variant HCL has a more varied immunophenotype, often being negative for one or more of these markers. Cyclin D1 staining is characteristically positive, but the t(11;14) is absent. | t(11;14) is absent. Virtually all HCL have BRAF V600E mutation. HCL variants usually lack the BRAF V600E mutation, but are associated with mutations in MAP2K1. |
| Lymphoplasmacytic lymphoma | Peripheral blood involvement is usually less prominent; circulating malignant cells usually have a plasmacytoid appearance ≥10% infiltration by small lymphocytes, plasmacytoid lymphocytes, and plasma cells, with variable numbers of admixed immunoblasts. Characteristic (but not pathognomonic) hyperplasia of mast cells in marrow. Lymph nodes are usually diffusely effaced. Proliferation centers and marginal zone type differentiation are absent. | Lacks CD23 expression and stains strongly for surface IgM, CD20, and cytoplasmic Ig. Express pan B cell antigens (CD19, CD20, CD22, CD79a). Most, but not all, cases fail to express CD5. Variable expression of CD11c, CD43, CD25. Most cases express IgM; fewer express IgG or IgA. CD10 and cyclin D1 are not expressed. | Majority have a monoclonal IgM paraprotein. No specific chromosomal abnormalities. High fraction (>95%) associated with mutations in MYD88. |
| Splenic marginal zone lymphoma | Circulating tumor cells may resemble CLL/SLL cells. | Like CLL/SLL, express CD23 and CD43. Minor subset is CD5 positive, but unlike CLL/SLL, typically has bright surface membrane immunoglobulin and CD20. Cyclin D1 staining is negative. | No specific chromosomal abnormalities. |
| Follicular lymphoma | Nodular growth pattern of follicle center cells (centrocytes and centroblasts). | Typically express CD10, HLA-DR, pan B cell antigens (CD19, CD20, CD79a), CD21, and surface IgM, IgG, or IgA. | t(14;18) |
| Histologic transformation to diffuse large B cell lymphoma | Large, transformed B cells with prominent nucleoli and basophilic cytoplasm demonstrating a diffuse growth pattern and a high (>40%) proliferation fraction. | Express pan B cell antigens (CD19, CD20, CD79a), CD45, and monoclonal surface membrane IgM. Some cases will demonstrate CD5. | Genetic abnormalities varied. |
TCR: T cell receptor; Ig: immunoglobulin.
* Disagreements among hematopathology groups have led to two main competing classification systems, the International Consensus Classification (ICC)[1] and the World Health Organization (WHO) classification, 5th edition[2], which have different approaches to B-cell prolymphocytic leukemia (B-PLL) and variant hairy cell leukemia (HCL-v). The ICC maintain B-PLL and HCL-v as unique entities, as in the 4th edition of the WHO classification, whereas the 5th edition of the WHO classification lumps B-PLL and HCL-v together in a new provisional entity, "splenic B-cell lymphoma/leukemia with prominent nucleoli".آیا می خواهید مدیلیب را به صفحه اصلی خود اضافه کنید؟
