Hi, just wanted to chime in about your question regarding the prognostic significance of the lymphocytosis. Golden Retrievers are one of the more common breeds to develop T zone lymphoma, which has a much more indolent course...prognosis is often years with no treatment or minimal treatment (prednisone or leukeran). If the clients are interested in typing the lymphoma, this is done by Flow Cytometry through Anne Avery's lab at Colorado State University. You can call them for details on how to submit - sample has to be overnighted, and cells from needle aspirate suspended in serum. Alternatively, if the whole lymph node was removed and submitted, the pathologist should be able to tell you if it is a T zone lymphoma. You can also have flow cytometry performed no the blood as long as the lymphocytosis is still present.
Here are a few articles describing canine T Zone lymphoma
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5053923/
Abstract:
Clinical and histopathological characteristics of 16 dogs with nodal paracortical (T-zone) lymphoma (TZL) were evaluated. At initial examination, generalized lymphadenopathy was found in all dogs, and peripheral lymphocytosis was found in 10 of the 16 dogs. At initial diagnosis or during the disease course, 8 dogs (50%) were affected with demodicosis. Immunohistochemical analysis for CD3, CD20 and CD25 was performed for 6 dogs with TZL; the tumor cells were positive for CD3 and CD25 and negative for CD20. Median overall survival time was 938 days. A watchful waiting approach was adopted for 6 cases (38%), and 5 of the 6 dogs were still alive at the end of follow-up. The clinical course of TZL in dogs is generally indolent; however, many cases develop a variety of infectious and other neoplastic diseases after the diagnosis of TZL.
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https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4895451/
J Vet Intern Med. 2014 May-Jun;28(3):878-86. doi: 10.1111/jvim.12343. Epub 2014 Mar 21.
Canine T-zone lymphoma: unique immunophenotypic features, outcome, and population characteristics.
Seelig DM1, Avery P, Webb T, Yoshimoto J, Bromberek J, Ehrhart EJ, Avery AC.
Author information
Abstract
BACKGROUND:
Canine T-cell lymphoma (TCL) is clinically and histologically heterogeneous with some forms, such as T-zone lymphoma (TZL), having an indolent course. Immunophenotyping is an important tool in the classification of TCL in people, and can be equally useful in dogs.
HYPOTHESIS/OBJECTIVES:
We hypothesized that loss of expression of the CD45 antigen is a specific diagnostic feature of TZL.
ANIMALS:
Twenty dogs with concurrent histology and immunophenotyping by flow cytometry were studied in depth. An additional 494 dogs diagnosed by immunophenotyping were used to characterize the population of dogs with this disease.
METHODS:
Lymph node biopsies from 35 dogs with TCL were classified by 2 pathologists using WHO criteria. Twenty lymph nodes were from dogs with CD45- TCL and 15 were from CD45+ TCL. The pathologists were blinded to the flow cytometry findings. Outcome information was sought for the 20 dogs with CD45- lymphoma, and population characteristics of the additional 494 dogs were described.
RESULTS:
All 20 CD45- cases were classified as TZL. The 15 CD45+ cases were classified as aggressive TCL and are described in an accompanying paper. TZL cases had a median survival of 637 days. Examination of 494 additional dogs diagnosed with TZL by immunophenotyping demonstrated that 40% of cases are in Golden Retrievers, are diagnosed at a median age of 10 years, and the majority have lymphadenopathy and lymphocytosis.
CONCLUSIONS:
TZL has unique immunophenotypic features that can be used for diagnosis.
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Vet Comp Oncol. 2016 Aug;14 Suppl 1:117-26. doi: 10.1111/vco.12155. Epub 2015 Jun 3.
Canine small clear cell/T-zone lymphoma: clinical presentation and outcome in a retrospective case series.
Martini V1, Marconato L2, Poggi A3, Riondato F3, Aresu L4, Cozzi M1, Comazzi S1.
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Abstract
Published studies, taken together, suggest the existence of a single canine lymphoma entity, with a small clear cell appearance by cytological evaluation, a histopathological T-zone pattern and an aberrant CD45-negative T-cell phenotype, mostly characterized by long-term survival. We describe clinical presentation and outcome in a retrospective case series of canine small clear cell/T-zone lymphoma. Despite the reported predisposition of Golden retriever, this breed was not represented in our case series. Most dogs presented with stage V disease, whereas only few had clinical signs or peripheral cytopenias. Blood was almost always more infiltrated than bone marrow. Median survival confirmed the favourable prognosis described in literature, but a few dogs died within a short time. Also, a subgroup of dogs developed second malignancies, eventually leading to death. We did not investigate possible prognostic factors because of the wide variety in treatments, and further studies are needed to identify high-risk animals.