. 2019 Nov 22:688–772. doi: 10.1016/B978-0-323-59496-7.00033-5

TABLE 33.3.

Histologic and Immunophenotypic Characteristics of Common Canine Non-Hodgkin’s Lymphomas in Relative Order of Frequency

Subtype	Typical Location	Histologic Architecture	Cellular Features	Immunophenotype
Diffuse large B-cell (DLBCL)	Usually multicentric lymphadenopathy	Diffuse	Large cells; round nuclei; one (central) or multiple nucleoli; high mitotic rate; “starry sky” appearance	CD1⁺, CD20⁺, CD21⁺, CD45⁺, CD79a⁺, Pax5⁺, MHCII⁺, CD18^low
Peripheral T-cell lymphoma-not otherwise specified (PTCL-NOS)	Usually multicentric lymphadenopathy	Diffuse	Variable size (small to large); irregular nuclei, variable chromatin, prominent nucleoli; varied mitotic activity	CD3⁺, CD79a^–, CD21^–, CD45⁺, CD5⁺, CD4^+/–, CD8^+/–, CD18^high, TCRαβ
Marginal zone lymphoma (MZL)	Nodal (nMZL) or splenic (sMZL) or extranodal mucosal	Nodular/ follicular	Mostly intermediate- sized cells- abundant pale cytoplasm; irregular nuclei with peripheralized chromatin and a single central nucleolus; rare mitotic figures (except nMZL)	CD1⁺, CD20⁺, CD21⁺, CD45⁺, CD79a⁺, MHCII⁺, CD18^intermediate
T-zone lymphoma (TZL)	Usually multicentric Lymphadenopathy	Nodular, paracortical, progressing to diffuse	Small to intermediate- sized cells; moderate amount of pale cytoplasm; oval to elliptical nuclei with sharp, shallow indentations; nucleoli and mitotic figures are sparse	CD45^–, CD3⁺, CD5⁺, CD21⁺, CD4⁺/^–, CD8^+/–
Precursor lymphoma^a	Multicentric and/or leukemia	Diffuse and/or leukemia	Intermediate-sized cells; round nuclei; scant Cytoplasm; high mitotic rate	If T-cell: CD45⁺, CD34⁺/^–, CD5^+/–, CD3⁺/^–, CD4^+/–, CD8^– If B-cell: CD45⁺, CD18⁺, CD34⁺/^–, CD79a⁺, CD21^+/–, CD20^+/–
Mantle cell lymphoma (MCL)	Splenic white pulp	Nodular/ follicular	Small to intermediate- sized cells; scant cytoplasm; round nuclei with dense chromatin, inconspicuous nucleoli; varied mitotic rate	CD20⁺, CD21⁺, CD45⁺, CD79a⁺, MHCII⁺
Follicular lymphoma	Lymphadenopathy, solitary or multiple	Nodular/ follicular	Mixed—mostly small cells with clear cytoplasm, pale chromatin, and inconspicuous nucleoli (centrocytes) with fewer large cells with dark blue cytoplasm, vesicular nuclei, and 1–3 nucleoli (centroblasts)	CD20⁺, CD21⁺, CD45⁺, CD79a⁺, MHCII⁺

Precursor lymphoma includes lymphoblastic B- or T-cell lymphomas and B- or T-cell acute leukemias.

Adapted with permission from Seelig DM, Avery AC, Ehrhart EJ, Linden MA. The comparative diagnostic features of canine and human lymphoma. Vet Sci. 2016;3: Epub ahead of print. https://doi.org/10.3390/vetsci3020011; and Burkhard MJ, Bienzle D. Making sense of lymphoma diagnostics in small animal patients. Vet Clin North Am Small Anim Pract. 2013;43:1331-1347.