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Periódicos Brasileiros em Medicina Veterinária e Zootecnia

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  3. Acta Scientiae Veterinariae
  4. Vol. 48 (2020) - Fascículo suppl.1

Clinical, cytological, histopathological and immunohistochemical features of a T-Zone lymphoma in a mixed-breed dog

Monteiro, Mariana CunhaGorza, Leonardo LimaMerísio, Alice Correa RasseleFlecher, Mayra CunhaHorta, Rodrigo dos Santos

Background: Non-Hodgkin lymphoma are a group of lymphoid neoplasms originating 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 this study was to report a TZL case in a 9-year-old male mixed breed dog, submitted to clinical follow-up and chemotherapy. Case: A 9-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 on 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 “hand-mirror” or “comet tail”, compatible with lymphocytic lymphoma (low grade) and suggestive of TZL, in the three assessed lymph nodes. The histopathological and immunohistochemical examination, of the mandibular lymph node were chosen to confirm the diagnosis. In histopathology it was observed that 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 in 48% of neoplastic cells, but negative for CD20, CD79a, CD45, MUM-1 and...(AU)

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