Clinical, Cytological, Histopathological and Immunohistochemical Features of a T-Zone Lymphoma in a Mixed-Breed Dog
Background: Non-Hodgkin lymphoma are a group of lymphoid neoplasms originated from the proliferation of precursors or mature, T, B and/ or NK lymphocytes. T-Zone lymphoma (TZL) is characterized as an indolent lymphoma due to its slow progression and poor chemotherapy´s response. Dogs affected by this neoplasm may live for many years without clinical signs and are often underdiagnosed. The aim of the present article is report a TZL case in a nine-year old male mixed breed dog, submitted to clinical follow-up and chemotherapy.
Case: A nine-year old male mixed-breed dog was presented due to the observation of an increased left mandibular lymph node. The previous cytological examination was suggestive of reactive hyperplasia and histopathological examination, by incisional biopsy, compatible with lymphocytic low-grade lymphoma. Physical examination revealed enlarged and firm left mandibular lymph node and adequate physical condition.
A cytological examination was performed in the mandibular and both popliteal lymph nodes and revealed many small lymphocytes with hyperchromatic chromatin, rarely evident nucleolus and whose cytoplasm often projected in the form of a “hind-mirror” or “comet tail”, compatible with lymphocytic lymphoma (low grade) and suggestive of TZL, in the both lymph nodes. The histopathological and immunohistochemical examination, of the mandibular lymph node, were chosen to confirm the diagnosis. At histopathology it was observed 40% of the sample contained a monotonous cell population, composed by small lymphocytes, with some presenting “hand-mirror” morphology. Two mitotic figures were evidenced per field of high magnification (40x), inferring a low-grade disease. Immunohistochemical analysis revealed neoplastic proliferation with immunolabeling of CD3 lymphocytes and positivity for Ki-67, but negative for CD20, CD79a, CD45, MUM-1 and PAX-5. Although there is no consensus about requirements and treatment´s efficacy, it has been chosen to treat the dog with chlorambucil, because of the elevated Ki-67 value (48%). The patient obtained a free-progression interval higher than 820 days, from the earlier investigations of lymphadenopathy, with excellent quality of life and no side effects related to the use of chlorambucil.
Discussion: Although TZL is a common subtype of lymphoproliferative disease in dog, it is still underdiagnosed. The TZL diagnosis can be suggested by cytology, from the disclosures in neoplastic cells of a cytoplasmic projections, recognized as a “hand-mirror” or “comet tail”, corroborated with the present case, however the histopathology is confirmatory. Immunohistochemistry in which the neoplasm cells showed a positive immunolabeling for CD3 and negative for CD79a, CD20, CD45, MUM1 and PAX5, as evidenced in this report, confirming the T-cell origin. According to the literature, lymphomas composed by small clear cells and cytoplasm projecting by cytology, immunolabeling CD3 and CD25 positive and CD45 negative are, together, findings that confirmed TZL. The biological behaviour of indolent lymphoma is still largely unknown, however the prognosis of dogs, with indolent lymphoma of T or B cells, seems to be favourable. Studies showed different days of median overall survival, such as 760 days and 4.4 years. In the present case, the dog showed 820 days, confirming the good prognosis and an indolent behavoiur. Aggressive chemotherapy protocols are not necessary for such cases and the treatment with chlorambucil, without the association of prednisolone, has been well tolerated by the patient, which showed no side effects until the moment.
Flood-Knapik K.E., Durham A.C., Gregor T.P., Sánchez M.D., Durney M.E. & Sorenmo K.U. 2013. Clinical, Histopathological and Immunohistochemical Characterization of Canine Indolent Lymphoma. Veterinary and Comparative Oncology. 11:272-86.
Martini V., Marconato L., Poggi A., Riondato F., Aresu L., Cozzi M. & Comazzi S. 2015. Canine Small Clear cell/T-zone Lymphoma: Clinical presentation and Outcome in a Retrospective Case Series. Veterinary and Comparative Oncology. 14: 117-126.
Mizutani N., Goto-Koshino Y., Takahashi M., Uchida K. & Tsujimoto H. 2016. Clinical dn Histopathological Evaluation of 16 Dogs With T-zone Lymphoma. The Journal of Veterinary Medicine Science. 78: 1237-1244.
Ponce F., Magnol J.P., Ledieu D., Marchal T., Turinelli V., Chalvet-Monfray K. & Fournel-Fleury C. 2004. Prognostic Significance of Morphological Subtypes in Canine Malignant Lymphoma During Chemotherapy. Veterinary Journal. 167: 158-166.
Ponce F., Marchal T., Magnol J.P., Turinelli V., Ledieu D., Bonnefont C., Pastor M., Delignette M.L. & Fournel-Fleury C. 2010. A Morphological Study of 608 Cases of Canine Malignant Lymphoma in France With a Focus on Comparative Similarities Between Canine and Human Lymphoma Morphology. Veterinary Pathology. 47: 414-433.
Savage K.J., Ferreri A.J.M., Zinzani P.L. & Pileri S.A. 2011. Peripheral T-cell lymphoma- Not otherwise specified. Critical Reviews in Oncology/Hematology. 79: 321-329.
Seelig D.M., Avery P.R., Webb T., Yoshimoto J., Bromberek J., Ehrhart E.J. & Avery A.C. 2014. Canine T-zone Lymphoma: Unique Immunophenotypic Features, Outcome, and Population Characteristics. Journal of Veterinary Internal Medicine. 28: 878-886.
World Health Organization. 2017. Classification of Tumours of Haematopoietic and Lymphoid Tissues. Geneva. 4th edn Report. (WHO Classification of Tumours). 586p.
Vail D.M., Pinkerton M.E. & Young K.M. 2013. Canine lymphoma and leukemia. In: Withrow & MacEwen´s Small Animal Clinical Oncology. 5th edn. Philadelphia: W.B. Saunders Co., pp. 611-628.
Van Stee L.L., Boston S.E., Singh A., Romanelli G., Rubio-Guzman A. & Scase TJ. 2015. Outcome and Prognostic Factors for Canine Splenic Lymphoma Treated by Splenectomy (1995-2011). Veterinary Surgery. 44: 976-982.
Valli V.E., Vernau W., de Loremier L.P., Graham P.S. & Moore P.F. 2006. Canine Indolent Nodular Lymphoma. Veterinary Pathology. 43: 241-56.
Valli V.E., Kass P.H., Myint M.S. & Scott F. 2013. Canine Lymphomas: Association of Classification Type, Disease Stage, Tumor Subtype, Mitotic Rate, and Treatment With Survival. Veterinary Pathology. 50: 738-748.
Valli VE, Bienzle D, Meuten DJ. 2017. Tumors of the Hemolymphatic System. In: Meuten Tumors in Domestic Animals. 5th edn. Iowa: John Wiley & Sons, Wiley Blackwell. pp.203-210.
How to Cite
This journal provides open access to all of its content on the principle that making research freely available to the public supports a greater global exchange of knowledge. Such access is associated with increased readership and increased citation of an author's work. For more information on this approach, see the Public Knowledge Project and Directory of Open Access Journals.
We define open access journals as journals that use a funding model that does not charge readers or their institutions for access. From the BOAI definition of "open access" we take the right of users to "read, download, copy, distribute, print, search, or link to the full texts of these articles" as mandatory for a journal to be included in the directory.
La Red y Portal Iberoamericano de Revistas Científicas de Veterinaria de Libre Acceso reúne a las principales publicaciones científicas editadas en España, Portugal, Latino América y otros países del ámbito latino