<b>LEUCEMIA LINFOBLÁSTICA AGUDA DE IMUNOFENÓTIPO T ABERRANTE EM CADELA</b>

Acute lymphoblastic leukemia (ALL) is a rare hematological neoplasm characterized by the disordered proliferation of lymphoblasts in the bone marrow and subsequent release into peripheral blood. This report describes the case of an 8-year-old German Shepherd diagnosed with ALL with an aberrant T-cell immunophenotype (CD3+/CD4-/CD8-/CD34+). The diagnosis was confirmed by flow cytometry, following laboratory results indicating extreme leukocytosis (90,500 leukocytes/μL) and 99% atypical lymphocytes. Palliative treatment with prednisone (2 mg/kg/day) and chlorambucil (Leukeran®) (6mg/m²/orally/once daily) was instituted to manage clinical signs, resulting in a reduction of circulating atypical lymphocytes. ALL is a biologically aggressive and rapidly progressing neoplasm. This report highlights the importance of early identification of ALL and the use of advanced techniques such as flow cytometry for the diagnosis and prognosis of these types of neoplasms.