Characteristics of lymphoma/leukemia types
| Cell type . | Features . | Characteristics . |
|---|---|---|
| B-cell neoplasms | ||
| Precursor B cell | ||
| Precursor B cell lymphoblastic lymphoma/ leukemia (Pre-B LBL) | Other nomenclature | Lymphoblastic lymphoma; lymphoblastic leukemia |
| Occurrence | Uncommon spontaneous neoplasm of inbred mice. Frequent in some GEM and mice infected with acutely transforming MuLV | |
| Necropsy findings | Splenomegaly, generalized lymphadenopathy, usually with extensive spread to liver, kidney, and lungs, sometimes to meninges with skull exostoses and hind limb paralysis; leukemic form in about one third of cases | |
| Cell size | Medium, uniform | |
| Cytoplasm | Scant | |
| Nuclei | Round or ovoid; chromatin fine | |
| Nucleoli | Variable, often single, central and prominent but sometimes small and multiple | |
| Mitoses | Numerous | |
| Pattern | Diffuse, sometimes starry sky because of apoptosis | |
| Phenotype | Immature B cell, sIg−B220+ CD19+ CD43± Ly6d (ThB)+, Tdt+ | |
| Molecular | Clonal precursor B cell, IgH G/R, IgK G/G | |
| Characteristic | High grade | |
| Presumed cell of origin | Bone marrow precursor B-cell lymphoblast | |
| Differential diagnosis | Histologically and cytologically indistinguishable from most pre-T LBL, BL, and BLL, but CD3− sIg− cytTdT+ | |
| Human counterpart and commentary | Precursor B-cell lymphoblastic lymphoma and leukemia. The use of the same name in the 2 species seems appropriate because of highly similar histologic, cytologic, phenotypic, and molecular features. | |
| Mature B cell | ||
| Small B-cell lymphoma | Other nomenclature | Small lymphocytic lymphoma; well-differentiated lymphocytic lymphoma |
| (SBL; Figure 2A) | Occurrence | Uncommon spontaneous neoplasm of mice; not yet reported for GEM |
| Necropsy findings | Splenomegaly and, in more advanced cases, lymphadenopathy, sometimes with hepatomegaly; one third with blood phase but bone marrow involvement uncommon | |
| Cell size | Small, uniform size and round shape | |
| Cytoplasm | Scant, basophilic | |
| Nuclei | Round; clumped chromatin | |
| Nucleoli | Inconspicuous | |
| Mitoses | Few | |
| Pattern | Diffuse | |
| Phenotype | Mature B cell, sIg+ B220+CD19+ | |
| Molecular | Clonal, mature B cell, IgH R/R, IgK R/R | |
| Characteristic | Low grade, but can be widespread and aggressive if in leukemic phase | |
| Presumed cell of origin | Small recirculating naive or memory B cell | |
| Differential diagnosis | Small T-cell lymphoma but sIg+ CD3− | |
| Human counterpart and commentary | There are cytologic similarities to human chronic lymphocytic leukemia (CLL)/small lymphocytic leukemia (SLL) but clear differences in organ involvement, histologic features, and immunophenotype. Human SLL of the B CLL type has 100% bone marrow and peripheral blood involvement. Histologically, human SLL exhibits occasional pseudo-follicles in some cases, a feature not seen in mice. Human SLL is IgD+, whereas mouse small B-cell lymphoma is not. Human CLL/SLL is considered a single disease in an individual patient, although clinically meaningful distinctions among patients can be made on the basis of genetic lesions and mutated IgV region sequences. In mice, SBL is a disease of secondary lymphoid tissues that may have a blood phase. These many differences led to the choice of a different name for the mouse small B-cell lymphoma. | |
| Splenic marginal zone lymphoma | Other nomenclature | None |
| (SMZL; Figure 2B-D) | Occurrence | Common in a few inbred congenic and recombinant inbred strains as well as some GEM |
| Necropsy findings | Large spleen, occasional splenic node involvement but other nodes and tissues usually negative | |
| Cell size | Medium, uniform | |
| Cytoplasm | Abundant, grayish to pale eosinophilic | |
| Nuclei | Round to ovoid; chromatin stippled to vesicular | |
| Nucleoli | Not prominent | |
| Mitoses | Few | |
| Pattern | Initially restricted to the marginal zone; later invasive into white and red pulp | |
| Phenotype | Mature B cell, sIgM+ B220+ CD19+ | |
| Molecular | Clonal, mature B cell, IgH R/R, IgK R/R | |
| Characteristic | Uniform, grayish to pale eosinophilic cytoplasm, low grade initially with progression to high grade with centroblastic morphology and increases in mitotic figures | |
| Presumed cell of origin | Splenic marginal zone B cell | |
| Differential diagnosis | None | |
| Human counterpart and commentary | Mouse SMZL and human MZL of mucosa-associated lymphoid tissue (MALT) type seen to clearly originate from cells of the marginal zone.8,38 39 In contrast, human SMZL may most often result from colonization of the marginal zone by follicular or mantle cell lymphoma rather than being a lymphoma derived from marginal zone B cells.38 Human splenic lymphomas with similarities to mouse SMZL have been observed (N.L.H., unpublished observations, August, 2000) but differed from those defined in the WHO classification as splenic MZL. SMZL is the only well-defined form of MZL in mice. Helicobacter-associated MALT accumulations have been reported but are not yet shown to be clonal.40 | |
| Follicular B-cell lymphoma (FBL; Figure 2E, F) | Other nomenclature | Centroblastic/centrocytic lymphoma; follicular lymphoma; follicular center cell lymphoma, small cell or mixed; reticulum cell sarcoma, type B; lymphoma-pleiomorphic |
| Occurrence | Most common spontaneous lymphoma in many commonly used inbred strains; occurs in some GEM | |
| Necropsy findings | Increasingly enlarged spleen with prominent white pulp that can be seen as white mottling or nodules representing individual enlarged follicles; sometimes nodular enlarged mesenteric lymph nodes; sometimes enlarged Peyer patches | |
| Cell size | Small or large | |
| Cytoplasm | Scant; large cells basophilic or eosinophilic | |
| Nuclei | Cleaved with clumped chromatin or noncleaved, round with vesicular chromatin | |
| Nucleoli | Inconspicuous in cleaved cells or usually two prominent and attached to the nuclear membrane in round, noncleaved cells | |
| Mitoses | Variable; none among centrocytes but increasing with frequency of centroblasts | |
| Pattern | Diffuse within splenic white pulp; rare nodular areas in lymph nodes but usually diffuse | |
| Phenotype | Mature B cell, sIgM+ B220+ CD19+; infiltrating T cells can be numerous | |
| Molecular | Clonal, mature B cell, IgH R/R, IgK R/R | |
| Characteristic | Low-grade, mixed cell populations resembling those of germinal center, including centrocytes, centroblasts, and immunoblasts; < 50% of cells are centroblasts or immunoblasts | |
| Presumed cell of origin | Germinal center B cells, but rarely seen in conjunction with clearly defined germinal centers | |
| Differential diagnosis | Diffuse large B-cell lymphomas of centroblastic type at the lower end of centroblast frequency | |
| Human counterpart and commentary | The diagnosis of human follicular lymphoma is based on the recognition in lymph node of follicular structures generated by transformed B cells, follicular dendritic cells, and T cells. The B-cell component consists of a cell mixture with cytologic features of germinal center centrocytes and centroblasts. A diffuse variant of human follicular lymphoma has been described, but it is very rare.41 The cytology of the mouse lymphoma is similar to this variant in that follicular structures are not seen, and white pulp involvement is diffuse. Suggestions of follicular structure are seen rarely in lymph nodes. There is no published immunohistochemical documentation of follicular dendritic cells in the mouse lymphomas, although they occur in normal germinal centers of the mouse. Follicular lymphoma in humans is regularly associated with chromosomal translocations, most commonly t(14;18) involving BCL2, a genetic marker not found in a substantial series of mouse FBL (Pattengale PK, unpublished observations, August, 2000). | |
| Diffuse large B-cell lymphoma (DLBCL) | ||
| Centroblastic (CB; Figure 3A) | Other nomenclature | Follicular center cell lymphoma, large cell; centroblastic lymphoma |
| Occurrence | Common in inbred strains; some GEM | |
| Necropsy findings | Splenomegaly and abdominal lymphadenopathy | |
| Cell size | Medium | |
| Cytoplasm | Scant | |
| Nuclei | Round, vesicular | |
| Nucleoli | Prominent, often 2 nucleoli adherent to the nuclear membrane | |
| Mitoses | Numerous | |
| Pattern | Diffuse | |
| Phenotype | Mature B cell, sIgM+ B220+ CD19+ | |
| Molecular | Clonal, mature B cell, IgH R/R, IgK R/R | |
| Characteristic | Diffuse involvement of the splenic white pulp, progressive effacement of lymph node architecture; 50% or more of cells are centroblasts, less than 10% of cells are immunoblasts. | |
| Presumed cell of origin | Germinal center B cell but can also derive from splenic marginal zone B cell | |
| Differential diagnosis | FBL and SMZL with high proportions of centroblasts and other types of DLBCL | |
| Human counterpart and commentary | DLBCL, centroblastic variant. In the mouse, this diagnosis has been associated with progression of FBL and SMZL, whereas others have been described simply as diffuse.42 The diagnosis has been made for lymphomas with more than 50% centroblasts in spleen. | |
| Immunoblastic | Other nomenclature | Immunoblastic lymphoma |
| (IB; Figure 3B) | Occurrence | Rare in most inbred strains and GEM |
| Necropsy findings | Splenomegaly, lymphadenopathy, extensive infiltration of nonlymphoid tissues | |
| Cell size | Large | |
| Cytoplasm | Abundant | |
| Nuclei | Round; chromatin vesicular | |
| Nucleoli | Prominent, magenta, often bar shaped, attached to nuclear membrane at one side | |
| Mitoses | Numerous | |
| Pattern | Diffuse; numerous immunoblasts admixed with a high proportion of centroblasts | |
| Phenotype | Mature B cell, sIgM+ B220+ CD19+cytIg+ | |
| Molecular | Clonal, mature B cell, IgH R/R, IgK R/R | |
| Characteristic | High grade; large noncohesive cells, many in apoptosis with a degree of starry sky | |
| Presumed cell of origin | Germinal center or postgerminal center B cell | |
| Differential diagnosis | Anaplastic plasmacytoma, other types of DLBCL | |
| Human counterpart and commentary | DLBCL-immunoblastic morphologic variant; the high proportion of immunoblasts seen in the human disease is rarely seen in mice. | |
| Histiocyte-associated | Other nomenclature | DLCL(HS) |
| (HA; Figure 3C) | Occurrence | Highly variable incidence in inbred strains and common in some GEM |
| | Necropsy findings | Splenomegaly greater than lymphadenopathy, frequent liver involvement with characteristic solid areas |
| Cell size | Large histiocytes (macrophages) admixed with centroblastic and immunoblastic B cells and variable numbers of smaller T cells; foreign body giant cells common | |
| Cytoplasm | Histiocytes abundant, eosinophilic, often vacuolated; scant for B cells | |
| Nuclei | Round, vesicular chromatin | |
| Nucleoli | Prominent, as for other DLBCL | |
| Mitoses | Numerous | |
| Pattern | Nodular, replacing splenic white and red pulp, often more diffuse in nodes; invasive around larger vessels and diffuse through sinusoids | |
| Phenotype | sIgM+ B220+CD19+ | |
| Molecular | Clonal, mature B cell, IgH R/R, IgK R/R; some with clonal TCRβ R/R | |
| Characteristic | Sheets of pink, vacuolated histiocytes varying from fusiform to round with substantial numbers of lymphocytes; > 50% of cells are histiocytes | |
| Presumed cell of origin | Germinal center or postgerminal center B cells | |
| Differential diagnosis | Other types of DLBCL | |
| Human counterpart and commentary | Histiocyte-rich DLBCL would be closest, but the malignant B-cell population in humans is only 5% to 10% of all cells. The frequency of histiocytes is never more than 70% in the mouse. There are 2 histologically indistinguishable subsets of this disease in mice, one with clonal populations of T cells and one without.22In mice, there also appear to be cases of T-cell–rich DLBCL with few if any histiocytes.21 Macrophages are not considered to be neoplastic, but there is no convincing evidence for or against this possibility. | |
| Primary mediastinal (thymic) diffuse | Other nomenclature | None |
| large B-cell lymphoma (PM; Figure 3D) | Occurrence | C57BL/6 mice infected helper-free with the replication-defective MuLV responsible for MAIDS (H.C.M., S. Chattopadhyay, unpublished observations, May 7, 2002.) |
| Necropsy findings | Thymic enlargement, very rarely with enlarged parathymic nodes or with spleen or liver involvement | |
| Cell size | Medium to large | |
| Cytoplasm | Scant to moderate | |
| Nuclei | Round; fine to vesicular chromatin | |
| Nucleoli | Prominent | |
| Mitoses | Numerous | |
| Pattern | Partial or complete effacement of normal thymic architecture, beginning in medulla | |
| Phenotype | Mature B cell, B220+ | |
| Molecular | Clonal, mature B cell, IgH R/R, IgK R/R | |
| Characteristic | Diffuse, starry sky | |
| Presumed cell of origin | Thymic B cell | |
| Differential diagnosis | Polyclonal MAIDS; thymic infiltration by DLBCL of nonthymic origin | |
| Human counterpart and commentary | Mediastinal large B-cell lymphoma is a possibility. Sclerosis, which is highly variable in the human disorder, is not seen in the mouse disease. | |
| Classic Burkitt lymphoma (BL; Figure 3E) | Other nomenclature | None |
| Occurrence | Frequent in some MYC transgenic mice | |
| Necropsy findings | Enlarged spleen, all nodes, and often thymus, usually severe | |
| Cell size | Medium/large, uniform | |
| Cytoplasm | Moderate | |
| Nuclei | Round; chromatin fine | |
| Nucleoli | Multiple, small, prominent | |
| Mitoses | Very numerous | |
| Pattern | Diffuse, starry sky | |
| Phenotype | Mature B cell, sIgM+ B220+ CD19+ | |
| Molecular | Clonal, mature B cell, IgH R/R, IgK R/R | |
| Characteristic | High grade, sheets of cells with extensive diffuse infiltration of lung, liver, and kidney | |
| Presumed cell of origin | Germinal center cells, perhaps founder cells, or postgerminal center B cell | |
| Differential diagnosis | Histologically similar to but often half again as large as precursor T cell or precursor B cell and most Burkittlike lymphoma but cytTdT−; MYC translocation or functional equivalent associated with characteristic morphology needed for diagnosis | |
| Human counterpart and commentary | Burkitt lymphoma is human counterpart. Because the disease in mice is induced by a myctransgene,25 this disease may represent one of the closest morphologic and molecular parallels between mouse and human diseases. The cell of origin is unknown in either species but may be the small germinal center B-cell blast. | |
| Burkittlike lymphoma (including mature | Other nomenclature | Lymphoblastic lymphoma; DLCL(LL) |
| B-cell lymphomas with lymphoblastic | Occurrence | Frequent in some inbred strains |
| morphology) (BLL; Figure 3F) | Necropsy findings | Generalized lymphadenopathy, splenomegaly |
| Cell size | Medium, uniform | |
| Nuclei | Round to ovoid; chromatin, fine | |
| Nucleoli | Single, central, prominent or several small | |
| Mitoses | Numerous | |
| Pattern | Diffuse, sometimes starry sky | |
| Phenotype | Mature B cell, sIgM+B220+ CD19+ | |
| Molecular | Clonal, mature B cell, IgH R/R, IgK R/R | |
| Characteristic | High grade, frequent leukemic phase | |
| Presumed cell of origin | Germinal center or postgerminal center B cell | |
| Differential diagnosis | Precursor T-cell and precursor B-cell lymphoblastic lymphoma but cytTdT−; also Burkitt lymphomas but no MYC translocation or functional equivalent | |
| Human counterpart and commentary | Unknown. May be mouse specific. Structural changes inBcl6 in some cases. See general discussion on diffuse large cell lymphoma. | |
| Plasma cell neoplasm | ||
| Plasmacytoma (PCT; Figure 4A,B) | Other nomenclature | Plasma cell lymphoma |
| Occurrence | Uncommon spontaneous tumor in certain inbred mice; readily induced with pristane given intraperitoneally in some inbred mice43 or by infection with acutely transforming retroviruses; appears at high frequency in some GEM | |
| Necropsy findings | Spontaneous disease with splenomegaly and/or lymphadenopathy; pristane-induced tumor appears in peritoneal granulomas; enlarged mesenteric and other nodes and Peyer patches in GEM; bone marrow involvement in v-abltransgenic mice | |
| Cell size | Generally medium-sized plasma cells | |
| Cytoplasm | Moderate, amphophilic, pyroninophilic | |
| Nuclei | Eccentric, round; chromatin, marginated, “clock face” in well-differentiated tumors | |
| Nucleoli | Variable | |
| Mitoses | Variable | |
| Pattern | Pristane-induced tumors with diffuse omental and serosal implants in granulomas exhibiting extensive histiocytosis, also diffuse in mesenteric lymph node, Peyer patches. Spontaneous PCT with splenic white pulp expansion and sometimes diffuse involvement of lymph nodes | |
| Phenotype | Secretory B cell, sIg−, cytIg+, CD138+, CD43±, Ly6D (ThB)+ | |
| Molecular | Immunoglobulin, clonal, mature B cell, IgH R/R, IgK R/R; T(12;15) in pristane induced43 | |
| Characteristic | Mixture of plasma cells and a few less mature forms. Rare bone marrow involvement | |
| Presumed cell of origin | Mature peripheral (nonbone marrow) plasma cell | |
| Differential diagnosis | Severe reactive plasmacytosis | |
| Human counterpart and commentary | Uncertain | |
| Extraosseous plasmacytoma (PCT-E) | Other nomenclature | None |
| Occurrence | Uncommon spontaneous tumor in some inbred mice. High frequency in interleukin 6 transgenic mice44 | |
| Necropsy findings | Enlarged spleen and nodes | |
| Cell size | Medium to large plasma cells | |
| Cytoplasm | Small to moderate, amphophilic | |
| Nuclei | Eccentric, round; chromatin marginated in more mature cells to more dispersed in less mature cells | |
| Nucleoli | Variable | |
| Mitoses | Variable | |
| Pattern | Nodular to diffuse involvement of splenic white pulp; lymph nodes show spreading from origins in medullary cords | |
| Phenotype | Secretory B cell, sIg−; cytIg+; CD138+ | |
| Molecular | Clonal mature B cell, IgH R/R, IgK R/R; commonly with t(12;15) | |
| Characteristic | Involvement of spleen and nodes rather than peritoneum | |
| Presumed cell of origin | Mature plasma cell | |
| Differential diagnosis | Reactive plasmacytosis | |
| Human counterpart and commentary | Extraosseous PCT | |
| Anaplastic plasmacytoma (PCT-A; | Other nomenclature | None |
| Figure 4C) | Occurrence | Reported rarely in inbred and GEM |
| Necropsy findings | Lymphadenopathy, splenomegaly | |
| Cell size | Medium to large | |
| Cytoplasm | Abundant | |
| Nuclei | Large, round; thick nuclear membrane | |
| Nucleoli | Prominent, round, central | |
| Mitoses | Numerous | |
| Pattern | Diffuse | |
| Phenotype | Early secretory B cell, sIgdull; cIg+; CD138dull | |
| Molecular | Clonal mature B cell, IgH R/R, IgK R/R | |
| Characteristic | Mixture of immunoblasts and plasmablasts with intermediate forms; more than 90% of cells are not mature plasma cells | |
| Presumed cell of origin | Mature peripheral (nonbone marrow) plasma cell | |
| Differential diagnosis | Immunoblastic lymphoma with differentiation | |
| Human counterpart and commentary | DLCL is plasmablastic morphologic variant. | |
| B–natural killer cell lymphoma (BNKL) | Other nomenclature | None |
| Occurrence | Thymectomized (SL/Kh × AKR/Ms)F1only45 | |
| Necropsy findings | Splenomegaly, lymphadenopathy, hepatomegaly | |
| Cell size | Large | |
| Cytoplasm | Abundant, pale blue | |
| Nuclei | Indented | |
| Nucleoli | Prominent, 2 to 4 | |
| Mitoses | Numerous | |
| Pattern | Diffuse | |
| Phenotype | B220+CD5+ IgM+ CD11b+ CD16+NK1.1+ | |
| Molecular | Clonal mature B cell, IgH R/R, IgK R/R | |
| Characteristic | High grade, diffuse with some starry sky appearance | |
| Presumed cell of origin | Unknown | |
| Differential diagnosis | T/NK lymphoma but sIg+CD3− | |
| Human counterpart and commentary | None known | |
| T-cell neoplasms | ||
| Precursor T cell neoplasm | ||
| Precursor T-cell lymphoblastic | Other nomenclature | Thymoma, lymphoblastic lymphoma, thymic lymphoma |
| lymphoma/leukemia (Pre-T LBL; | Occurrence | Some inbred strains; many GEM. Most common tumor induced by viruses, chemicals, radiation |
| Figure 4D) | Necropsy findings | Enlarged thymus, variable splenomegaly and lymphadenopathy |
| Cell size | Medium, uniform | |
| Cytoplasm | Scant | |
| Nuclei | Round; chromatin fine | |
| Nucleoli | Multiple, small/prominent; some with central, prominent nucleoli just as for pre-BLL | |
| Mitoses | Numerous | |
| Pattern | Diffuse, starry sky | |
| Phenotype | Immature T cell, CD3+, CD4−/CD8− double negative, CD4+/CD8+ double positive, or CD4 or CD8 single positive, TCR+, cytTdT+ | |
| Molecular | Clonal T cell, TCRβ R/R | |
| Characteristic | High grade, moderate starry sky, sheets of cells; perivascular infiltration of lung, liver, soft tissue | |
| Presumed cell of origin | Precursor intrathymic T cell but could derive from precursor cells in the bone marrow that home to thymus | |
| Differential diagnosis | Histologically indistinguishable from precursor B-cell lymphoblastic lymphoma/leukemia but CD3+; also very similar to Burkittlike lymphomas but sIg− | |
| Human counterpart and commentary | Precursor T-cell lymphoblastic lymphoma | |
| Mature T cell neoplasm | ||
| Small T-cell lymphoma (STL) | Other nomenclature | None |
| Occurrence | Rare in inbred strains | |
| Necropsy findings | Splenomegaly, lymphadenopathy, thymus not enlarged | |
| Cell size | Small | |
| Cytoplasm | Scant, basophilic | |
| Nuclei | Small; condensed chromatin | |
| Nucleoli | Inconspicuous | |
| Mitoses | Few | |
| Pattern | Diffuse | |
| Phenotype | Mature T cell, CD3+, TCR+, CD4+ or CD8+, cytTdT− | |
| Molecular | Clonal T cell, TCRβ R/R | |
| Characteristic | Low grade, resemble small mature lymphocytes | |
| Presumed cell of origin | Small recirculating T lymphocyte | |
| Differential diagnosis | Small B-cell lymphoma but CD3+ sIg− | |
| Human counterpart and commentary | This lymphoma may be unique to the mouse. | |
| T–natural killer cell lymphoma | Other nomenclature | None |
| (TNKL; Figure 4E) | Occurrence | IL-15 transgenic only46 47 |
| Necropsy findings | Splenomegaly, hepatomegaly | |
| Cell size | Medium to large | |
| Nuclei | Large, chromatin coarse | |
| Nucleoli | Multiple and prominent | |
| Mitoses | Numerous in marrow | |
| Pattern | Diffuse | |
| Phenotype | CD3+, TCRα/β+, CD8±, DX5± | |
| Molecular | TCRβ in about 50% of cases46 or no rearrangements47 | |
| Characteristic | Diffuse infiltration of spleen, nodes, and liver | |
| Human counterpart and commentary | Some similarities to T-cell large granular lymphocytic leukemia. In the mouse, origin is in the marrow, with blood disease evident before secondary involvement of lymphoid and other tissues. | |
| T-cell neoplasm, character undetermined | ||
| Large cell anaplastic lymphoma | Other nomenclature | None |
| (TLCA; Figure 4F) | Occurrence | Rare in inbred strains |
| Necropsy findings | Enlarged thymus, splenomegaly, lymphadenopathy | |
| Cell size | Large, pleomorphic | |
| Cytoplasm | Scant | |
| Nuclei | Large, round to irregular, vesicular | |
| Nucleoli | Single, very large, irregular in shape | |
| Mitoses | Very numerous | |
| Pattern | Diffuse, extensive starry sky | |
| Phenotype | Not known | |
| Molecular | Clonal T cell, TCRβ R/R | |
| Characteristic | High grade, starry sky, sheets of cells; diffuse infiltration, lung, liver, soft tissue | |
| Presumed cell of origin | Immature or mature cell is not known as analyses of cytTdT have not been performed | |
| Differential diagnosis | None | |
| Human counterpart and commentary | None. Not comparable to human anaplastic large cell lymphoma, T/null. |
| Cell type . | Features . | Characteristics . |
|---|---|---|
| B-cell neoplasms | ||
| Precursor B cell | ||
| Precursor B cell lymphoblastic lymphoma/ leukemia (Pre-B LBL) | Other nomenclature | Lymphoblastic lymphoma; lymphoblastic leukemia |
| Occurrence | Uncommon spontaneous neoplasm of inbred mice. Frequent in some GEM and mice infected with acutely transforming MuLV | |
| Necropsy findings | Splenomegaly, generalized lymphadenopathy, usually with extensive spread to liver, kidney, and lungs, sometimes to meninges with skull exostoses and hind limb paralysis; leukemic form in about one third of cases | |
| Cell size | Medium, uniform | |
| Cytoplasm | Scant | |
| Nuclei | Round or ovoid; chromatin fine | |
| Nucleoli | Variable, often single, central and prominent but sometimes small and multiple | |
| Mitoses | Numerous | |
| Pattern | Diffuse, sometimes starry sky because of apoptosis | |
| Phenotype | Immature B cell, sIg−B220+ CD19+ CD43± Ly6d (ThB)+, Tdt+ | |
| Molecular | Clonal precursor B cell, IgH G/R, IgK G/G | |
| Characteristic | High grade | |
| Presumed cell of origin | Bone marrow precursor B-cell lymphoblast | |
| Differential diagnosis | Histologically and cytologically indistinguishable from most pre-T LBL, BL, and BLL, but CD3− sIg− cytTdT+ | |
| Human counterpart and commentary | Precursor B-cell lymphoblastic lymphoma and leukemia. The use of the same name in the 2 species seems appropriate because of highly similar histologic, cytologic, phenotypic, and molecular features. | |
| Mature B cell | ||
| Small B-cell lymphoma | Other nomenclature | Small lymphocytic lymphoma; well-differentiated lymphocytic lymphoma |
| (SBL; Figure 2A) | Occurrence | Uncommon spontaneous neoplasm of mice; not yet reported for GEM |
| Necropsy findings | Splenomegaly and, in more advanced cases, lymphadenopathy, sometimes with hepatomegaly; one third with blood phase but bone marrow involvement uncommon | |
| Cell size | Small, uniform size and round shape | |
| Cytoplasm | Scant, basophilic | |
| Nuclei | Round; clumped chromatin | |
| Nucleoli | Inconspicuous | |
| Mitoses | Few | |
| Pattern | Diffuse | |
| Phenotype | Mature B cell, sIg+ B220+CD19+ | |
| Molecular | Clonal, mature B cell, IgH R/R, IgK R/R | |
| Characteristic | Low grade, but can be widespread and aggressive if in leukemic phase | |
| Presumed cell of origin | Small recirculating naive or memory B cell | |
| Differential diagnosis | Small T-cell lymphoma but sIg+ CD3− | |
| Human counterpart and commentary | There are cytologic similarities to human chronic lymphocytic leukemia (CLL)/small lymphocytic leukemia (SLL) but clear differences in organ involvement, histologic features, and immunophenotype. Human SLL of the B CLL type has 100% bone marrow and peripheral blood involvement. Histologically, human SLL exhibits occasional pseudo-follicles in some cases, a feature not seen in mice. Human SLL is IgD+, whereas mouse small B-cell lymphoma is not. Human CLL/SLL is considered a single disease in an individual patient, although clinically meaningful distinctions among patients can be made on the basis of genetic lesions and mutated IgV region sequences. In mice, SBL is a disease of secondary lymphoid tissues that may have a blood phase. These many differences led to the choice of a different name for the mouse small B-cell lymphoma. | |
| Splenic marginal zone lymphoma | Other nomenclature | None |
| (SMZL; Figure 2B-D) | Occurrence | Common in a few inbred congenic and recombinant inbred strains as well as some GEM |
| Necropsy findings | Large spleen, occasional splenic node involvement but other nodes and tissues usually negative | |
| Cell size | Medium, uniform | |
| Cytoplasm | Abundant, grayish to pale eosinophilic | |
| Nuclei | Round to ovoid; chromatin stippled to vesicular | |
| Nucleoli | Not prominent | |
| Mitoses | Few | |
| Pattern | Initially restricted to the marginal zone; later invasive into white and red pulp | |
| Phenotype | Mature B cell, sIgM+ B220+ CD19+ | |
| Molecular | Clonal, mature B cell, IgH R/R, IgK R/R | |
| Characteristic | Uniform, grayish to pale eosinophilic cytoplasm, low grade initially with progression to high grade with centroblastic morphology and increases in mitotic figures | |
| Presumed cell of origin | Splenic marginal zone B cell | |
| Differential diagnosis | None | |
| Human counterpart and commentary | Mouse SMZL and human MZL of mucosa-associated lymphoid tissue (MALT) type seen to clearly originate from cells of the marginal zone.8,38 39 In contrast, human SMZL may most often result from colonization of the marginal zone by follicular or mantle cell lymphoma rather than being a lymphoma derived from marginal zone B cells.38 Human splenic lymphomas with similarities to mouse SMZL have been observed (N.L.H., unpublished observations, August, 2000) but differed from those defined in the WHO classification as splenic MZL. SMZL is the only well-defined form of MZL in mice. Helicobacter-associated MALT accumulations have been reported but are not yet shown to be clonal.40 | |
| Follicular B-cell lymphoma (FBL; Figure 2E, F) | Other nomenclature | Centroblastic/centrocytic lymphoma; follicular lymphoma; follicular center cell lymphoma, small cell or mixed; reticulum cell sarcoma, type B; lymphoma-pleiomorphic |
| Occurrence | Most common spontaneous lymphoma in many commonly used inbred strains; occurs in some GEM | |
| Necropsy findings | Increasingly enlarged spleen with prominent white pulp that can be seen as white mottling or nodules representing individual enlarged follicles; sometimes nodular enlarged mesenteric lymph nodes; sometimes enlarged Peyer patches | |
| Cell size | Small or large | |
| Cytoplasm | Scant; large cells basophilic or eosinophilic | |
| Nuclei | Cleaved with clumped chromatin or noncleaved, round with vesicular chromatin | |
| Nucleoli | Inconspicuous in cleaved cells or usually two prominent and attached to the nuclear membrane in round, noncleaved cells | |
| Mitoses | Variable; none among centrocytes but increasing with frequency of centroblasts | |
| Pattern | Diffuse within splenic white pulp; rare nodular areas in lymph nodes but usually diffuse | |
| Phenotype | Mature B cell, sIgM+ B220+ CD19+; infiltrating T cells can be numerous | |
| Molecular | Clonal, mature B cell, IgH R/R, IgK R/R | |
| Characteristic | Low-grade, mixed cell populations resembling those of germinal center, including centrocytes, centroblasts, and immunoblasts; < 50% of cells are centroblasts or immunoblasts | |
| Presumed cell of origin | Germinal center B cells, but rarely seen in conjunction with clearly defined germinal centers | |
| Differential diagnosis | Diffuse large B-cell lymphomas of centroblastic type at the lower end of centroblast frequency | |
| Human counterpart and commentary | The diagnosis of human follicular lymphoma is based on the recognition in lymph node of follicular structures generated by transformed B cells, follicular dendritic cells, and T cells. The B-cell component consists of a cell mixture with cytologic features of germinal center centrocytes and centroblasts. A diffuse variant of human follicular lymphoma has been described, but it is very rare.41 The cytology of the mouse lymphoma is similar to this variant in that follicular structures are not seen, and white pulp involvement is diffuse. Suggestions of follicular structure are seen rarely in lymph nodes. There is no published immunohistochemical documentation of follicular dendritic cells in the mouse lymphomas, although they occur in normal germinal centers of the mouse. Follicular lymphoma in humans is regularly associated with chromosomal translocations, most commonly t(14;18) involving BCL2, a genetic marker not found in a substantial series of mouse FBL (Pattengale PK, unpublished observations, August, 2000). | |
| Diffuse large B-cell lymphoma (DLBCL) | ||
| Centroblastic (CB; Figure 3A) | Other nomenclature | Follicular center cell lymphoma, large cell; centroblastic lymphoma |
| Occurrence | Common in inbred strains; some GEM | |
| Necropsy findings | Splenomegaly and abdominal lymphadenopathy | |
| Cell size | Medium | |
| Cytoplasm | Scant | |
| Nuclei | Round, vesicular | |
| Nucleoli | Prominent, often 2 nucleoli adherent to the nuclear membrane | |
| Mitoses | Numerous | |
| Pattern | Diffuse | |
| Phenotype | Mature B cell, sIgM+ B220+ CD19+ | |
| Molecular | Clonal, mature B cell, IgH R/R, IgK R/R | |
| Characteristic | Diffuse involvement of the splenic white pulp, progressive effacement of lymph node architecture; 50% or more of cells are centroblasts, less than 10% of cells are immunoblasts. | |
| Presumed cell of origin | Germinal center B cell but can also derive from splenic marginal zone B cell | |
| Differential diagnosis | FBL and SMZL with high proportions of centroblasts and other types of DLBCL | |
| Human counterpart and commentary | DLBCL, centroblastic variant. In the mouse, this diagnosis has been associated with progression of FBL and SMZL, whereas others have been described simply as diffuse.42 The diagnosis has been made for lymphomas with more than 50% centroblasts in spleen. | |
| Immunoblastic | Other nomenclature | Immunoblastic lymphoma |
| (IB; Figure 3B) | Occurrence | Rare in most inbred strains and GEM |
| Necropsy findings | Splenomegaly, lymphadenopathy, extensive infiltration of nonlymphoid tissues | |
| Cell size | Large | |
| Cytoplasm | Abundant | |
| Nuclei | Round; chromatin vesicular | |
| Nucleoli | Prominent, magenta, often bar shaped, attached to nuclear membrane at one side | |
| Mitoses | Numerous | |
| Pattern | Diffuse; numerous immunoblasts admixed with a high proportion of centroblasts | |
| Phenotype | Mature B cell, sIgM+ B220+ CD19+cytIg+ | |
| Molecular | Clonal, mature B cell, IgH R/R, IgK R/R | |
| Characteristic | High grade; large noncohesive cells, many in apoptosis with a degree of starry sky | |
| Presumed cell of origin | Germinal center or postgerminal center B cell | |
| Differential diagnosis | Anaplastic plasmacytoma, other types of DLBCL | |
| Human counterpart and commentary | DLBCL-immunoblastic morphologic variant; the high proportion of immunoblasts seen in the human disease is rarely seen in mice. | |
| Histiocyte-associated | Other nomenclature | DLCL(HS) |
| (HA; Figure 3C) | Occurrence | Highly variable incidence in inbred strains and common in some GEM |
| | Necropsy findings | Splenomegaly greater than lymphadenopathy, frequent liver involvement with characteristic solid areas |
| Cell size | Large histiocytes (macrophages) admixed with centroblastic and immunoblastic B cells and variable numbers of smaller T cells; foreign body giant cells common | |
| Cytoplasm | Histiocytes abundant, eosinophilic, often vacuolated; scant for B cells | |
| Nuclei | Round, vesicular chromatin | |
| Nucleoli | Prominent, as for other DLBCL | |
| Mitoses | Numerous | |
| Pattern | Nodular, replacing splenic white and red pulp, often more diffuse in nodes; invasive around larger vessels and diffuse through sinusoids | |
| Phenotype | sIgM+ B220+CD19+ | |
| Molecular | Clonal, mature B cell, IgH R/R, IgK R/R; some with clonal TCRβ R/R | |
| Characteristic | Sheets of pink, vacuolated histiocytes varying from fusiform to round with substantial numbers of lymphocytes; > 50% of cells are histiocytes | |
| Presumed cell of origin | Germinal center or postgerminal center B cells | |
| Differential diagnosis | Other types of DLBCL | |
| Human counterpart and commentary | Histiocyte-rich DLBCL would be closest, but the malignant B-cell population in humans is only 5% to 10% of all cells. The frequency of histiocytes is never more than 70% in the mouse. There are 2 histologically indistinguishable subsets of this disease in mice, one with clonal populations of T cells and one without.22In mice, there also appear to be cases of T-cell–rich DLBCL with few if any histiocytes.21 Macrophages are not considered to be neoplastic, but there is no convincing evidence for or against this possibility. | |
| Primary mediastinal (thymic) diffuse | Other nomenclature | None |
| large B-cell lymphoma (PM; Figure 3D) | Occurrence | C57BL/6 mice infected helper-free with the replication-defective MuLV responsible for MAIDS (H.C.M., S. Chattopadhyay, unpublished observations, May 7, 2002.) |
| Necropsy findings | Thymic enlargement, very rarely with enlarged parathymic nodes or with spleen or liver involvement | |
| Cell size | Medium to large | |
| Cytoplasm | Scant to moderate | |
| Nuclei | Round; fine to vesicular chromatin | |
| Nucleoli | Prominent | |
| Mitoses | Numerous | |
| Pattern | Partial or complete effacement of normal thymic architecture, beginning in medulla | |
| Phenotype | Mature B cell, B220+ | |
| Molecular | Clonal, mature B cell, IgH R/R, IgK R/R | |
| Characteristic | Diffuse, starry sky | |
| Presumed cell of origin | Thymic B cell | |
| Differential diagnosis | Polyclonal MAIDS; thymic infiltration by DLBCL of nonthymic origin | |
| Human counterpart and commentary | Mediastinal large B-cell lymphoma is a possibility. Sclerosis, which is highly variable in the human disorder, is not seen in the mouse disease. | |
| Classic Burkitt lymphoma (BL; Figure 3E) | Other nomenclature | None |
| Occurrence | Frequent in some MYC transgenic mice | |
| Necropsy findings | Enlarged spleen, all nodes, and often thymus, usually severe | |
| Cell size | Medium/large, uniform | |
| Cytoplasm | Moderate | |
| Nuclei | Round; chromatin fine | |
| Nucleoli | Multiple, small, prominent | |
| Mitoses | Very numerous | |
| Pattern | Diffuse, starry sky | |
| Phenotype | Mature B cell, sIgM+ B220+ CD19+ | |
| Molecular | Clonal, mature B cell, IgH R/R, IgK R/R | |
| Characteristic | High grade, sheets of cells with extensive diffuse infiltration of lung, liver, and kidney | |
| Presumed cell of origin | Germinal center cells, perhaps founder cells, or postgerminal center B cell | |
| Differential diagnosis | Histologically similar to but often half again as large as precursor T cell or precursor B cell and most Burkittlike lymphoma but cytTdT−; MYC translocation or functional equivalent associated with characteristic morphology needed for diagnosis | |
| Human counterpart and commentary | Burkitt lymphoma is human counterpart. Because the disease in mice is induced by a myctransgene,25 this disease may represent one of the closest morphologic and molecular parallels between mouse and human diseases. The cell of origin is unknown in either species but may be the small germinal center B-cell blast. | |
| Burkittlike lymphoma (including mature | Other nomenclature | Lymphoblastic lymphoma; DLCL(LL) |
| B-cell lymphomas with lymphoblastic | Occurrence | Frequent in some inbred strains |
| morphology) (BLL; Figure 3F) | Necropsy findings | Generalized lymphadenopathy, splenomegaly |
| Cell size | Medium, uniform | |
| Nuclei | Round to ovoid; chromatin, fine | |
| Nucleoli | Single, central, prominent or several small | |
| Mitoses | Numerous | |
| Pattern | Diffuse, sometimes starry sky | |
| Phenotype | Mature B cell, sIgM+B220+ CD19+ | |
| Molecular | Clonal, mature B cell, IgH R/R, IgK R/R | |
| Characteristic | High grade, frequent leukemic phase | |
| Presumed cell of origin | Germinal center or postgerminal center B cell | |
| Differential diagnosis | Precursor T-cell and precursor B-cell lymphoblastic lymphoma but cytTdT−; also Burkitt lymphomas but no MYC translocation or functional equivalent | |
| Human counterpart and commentary | Unknown. May be mouse specific. Structural changes inBcl6 in some cases. See general discussion on diffuse large cell lymphoma. | |
| Plasma cell neoplasm | ||
| Plasmacytoma (PCT; Figure 4A,B) | Other nomenclature | Plasma cell lymphoma |
| Occurrence | Uncommon spontaneous tumor in certain inbred mice; readily induced with pristane given intraperitoneally in some inbred mice43 or by infection with acutely transforming retroviruses; appears at high frequency in some GEM | |
| Necropsy findings | Spontaneous disease with splenomegaly and/or lymphadenopathy; pristane-induced tumor appears in peritoneal granulomas; enlarged mesenteric and other nodes and Peyer patches in GEM; bone marrow involvement in v-abltransgenic mice | |
| Cell size | Generally medium-sized plasma cells | |
| Cytoplasm | Moderate, amphophilic, pyroninophilic | |
| Nuclei | Eccentric, round; chromatin, marginated, “clock face” in well-differentiated tumors | |
| Nucleoli | Variable | |
| Mitoses | Variable | |
| Pattern | Pristane-induced tumors with diffuse omental and serosal implants in granulomas exhibiting extensive histiocytosis, also diffuse in mesenteric lymph node, Peyer patches. Spontaneous PCT with splenic white pulp expansion and sometimes diffuse involvement of lymph nodes | |
| Phenotype | Secretory B cell, sIg−, cytIg+, CD138+, CD43±, Ly6D (ThB)+ | |
| Molecular | Immunoglobulin, clonal, mature B cell, IgH R/R, IgK R/R; T(12;15) in pristane induced43 | |
| Characteristic | Mixture of plasma cells and a few less mature forms. Rare bone marrow involvement | |
| Presumed cell of origin | Mature peripheral (nonbone marrow) plasma cell | |
| Differential diagnosis | Severe reactive plasmacytosis | |
| Human counterpart and commentary | Uncertain | |
| Extraosseous plasmacytoma (PCT-E) | Other nomenclature | None |
| Occurrence | Uncommon spontaneous tumor in some inbred mice. High frequency in interleukin 6 transgenic mice44 | |
| Necropsy findings | Enlarged spleen and nodes | |
| Cell size | Medium to large plasma cells | |
| Cytoplasm | Small to moderate, amphophilic | |
| Nuclei | Eccentric, round; chromatin marginated in more mature cells to more dispersed in less mature cells | |
| Nucleoli | Variable | |
| Mitoses | Variable | |
| Pattern | Nodular to diffuse involvement of splenic white pulp; lymph nodes show spreading from origins in medullary cords | |
| Phenotype | Secretory B cell, sIg−; cytIg+; CD138+ | |
| Molecular | Clonal mature B cell, IgH R/R, IgK R/R; commonly with t(12;15) | |
| Characteristic | Involvement of spleen and nodes rather than peritoneum | |
| Presumed cell of origin | Mature plasma cell | |
| Differential diagnosis | Reactive plasmacytosis | |
| Human counterpart and commentary | Extraosseous PCT | |
| Anaplastic plasmacytoma (PCT-A; | Other nomenclature | None |
| Figure 4C) | Occurrence | Reported rarely in inbred and GEM |
| Necropsy findings | Lymphadenopathy, splenomegaly | |
| Cell size | Medium to large | |
| Cytoplasm | Abundant | |
| Nuclei | Large, round; thick nuclear membrane | |
| Nucleoli | Prominent, round, central | |
| Mitoses | Numerous | |
| Pattern | Diffuse | |
| Phenotype | Early secretory B cell, sIgdull; cIg+; CD138dull | |
| Molecular | Clonal mature B cell, IgH R/R, IgK R/R | |
| Characteristic | Mixture of immunoblasts and plasmablasts with intermediate forms; more than 90% of cells are not mature plasma cells | |
| Presumed cell of origin | Mature peripheral (nonbone marrow) plasma cell | |
| Differential diagnosis | Immunoblastic lymphoma with differentiation | |
| Human counterpart and commentary | DLCL is plasmablastic morphologic variant. | |
| B–natural killer cell lymphoma (BNKL) | Other nomenclature | None |
| Occurrence | Thymectomized (SL/Kh × AKR/Ms)F1only45 | |
| Necropsy findings | Splenomegaly, lymphadenopathy, hepatomegaly | |
| Cell size | Large | |
| Cytoplasm | Abundant, pale blue | |
| Nuclei | Indented | |
| Nucleoli | Prominent, 2 to 4 | |
| Mitoses | Numerous | |
| Pattern | Diffuse | |
| Phenotype | B220+CD5+ IgM+ CD11b+ CD16+NK1.1+ | |
| Molecular | Clonal mature B cell, IgH R/R, IgK R/R | |
| Characteristic | High grade, diffuse with some starry sky appearance | |
| Presumed cell of origin | Unknown | |
| Differential diagnosis | T/NK lymphoma but sIg+CD3− | |
| Human counterpart and commentary | None known | |
| T-cell neoplasms | ||
| Precursor T cell neoplasm | ||
| Precursor T-cell lymphoblastic | Other nomenclature | Thymoma, lymphoblastic lymphoma, thymic lymphoma |
| lymphoma/leukemia (Pre-T LBL; | Occurrence | Some inbred strains; many GEM. Most common tumor induced by viruses, chemicals, radiation |
| Figure 4D) | Necropsy findings | Enlarged thymus, variable splenomegaly and lymphadenopathy |
| Cell size | Medium, uniform | |
| Cytoplasm | Scant | |
| Nuclei | Round; chromatin fine | |
| Nucleoli | Multiple, small/prominent; some with central, prominent nucleoli just as for pre-BLL | |
| Mitoses | Numerous | |
| Pattern | Diffuse, starry sky | |
| Phenotype | Immature T cell, CD3+, CD4−/CD8− double negative, CD4+/CD8+ double positive, or CD4 or CD8 single positive, TCR+, cytTdT+ | |
| Molecular | Clonal T cell, TCRβ R/R | |
| Characteristic | High grade, moderate starry sky, sheets of cells; perivascular infiltration of lung, liver, soft tissue | |
| Presumed cell of origin | Precursor intrathymic T cell but could derive from precursor cells in the bone marrow that home to thymus | |
| Differential diagnosis | Histologically indistinguishable from precursor B-cell lymphoblastic lymphoma/leukemia but CD3+; also very similar to Burkittlike lymphomas but sIg− | |
| Human counterpart and commentary | Precursor T-cell lymphoblastic lymphoma | |
| Mature T cell neoplasm | ||
| Small T-cell lymphoma (STL) | Other nomenclature | None |
| Occurrence | Rare in inbred strains | |
| Necropsy findings | Splenomegaly, lymphadenopathy, thymus not enlarged | |
| Cell size | Small | |
| Cytoplasm | Scant, basophilic | |
| Nuclei | Small; condensed chromatin | |
| Nucleoli | Inconspicuous | |
| Mitoses | Few | |
| Pattern | Diffuse | |
| Phenotype | Mature T cell, CD3+, TCR+, CD4+ or CD8+, cytTdT− | |
| Molecular | Clonal T cell, TCRβ R/R | |
| Characteristic | Low grade, resemble small mature lymphocytes | |
| Presumed cell of origin | Small recirculating T lymphocyte | |
| Differential diagnosis | Small B-cell lymphoma but CD3+ sIg− | |
| Human counterpart and commentary | This lymphoma may be unique to the mouse. | |
| T–natural killer cell lymphoma | Other nomenclature | None |
| (TNKL; Figure 4E) | Occurrence | IL-15 transgenic only46 47 |
| Necropsy findings | Splenomegaly, hepatomegaly | |
| Cell size | Medium to large | |
| Nuclei | Large, chromatin coarse | |
| Nucleoli | Multiple and prominent | |
| Mitoses | Numerous in marrow | |
| Pattern | Diffuse | |
| Phenotype | CD3+, TCRα/β+, CD8±, DX5± | |
| Molecular | TCRβ in about 50% of cases46 or no rearrangements47 | |
| Characteristic | Diffuse infiltration of spleen, nodes, and liver | |
| Human counterpart and commentary | Some similarities to T-cell large granular lymphocytic leukemia. In the mouse, origin is in the marrow, with blood disease evident before secondary involvement of lymphoid and other tissues. | |
| T-cell neoplasm, character undetermined | ||
| Large cell anaplastic lymphoma | Other nomenclature | None |
| (TLCA; Figure 4F) | Occurrence | Rare in inbred strains |
| Necropsy findings | Enlarged thymus, splenomegaly, lymphadenopathy | |
| Cell size | Large, pleomorphic | |
| Cytoplasm | Scant | |
| Nuclei | Large, round to irregular, vesicular | |
| Nucleoli | Single, very large, irregular in shape | |
| Mitoses | Very numerous | |
| Pattern | Diffuse, extensive starry sky | |
| Phenotype | Not known | |
| Molecular | Clonal T cell, TCRβ R/R | |
| Characteristic | High grade, starry sky, sheets of cells; diffuse infiltration, lung, liver, soft tissue | |
| Presumed cell of origin | Immature or mature cell is not known as analyses of cytTdT have not been performed | |
| Differential diagnosis | None | |
| Human counterpart and commentary | None. Not comparable to human anaplastic large cell lymphoma, T/null. |