Linfocitose extrema sugestiva de leucemia linfoblástica aguda em cão : relato de caso

Abstract

Background: Acute lymphoblastic leukemia (ALL) in dogs is an aggressive neoplasm characterized by the uncontrolled proliferation of lymphoblasts in the bone marrow, peripheral blood, and lymphatic tissues. Dogs with ALL present with lethargy, anorexia, weight loss, fever, pale mucous membranes, hepatomegaly, splenomegaly, and lymphadenopathy. ALL is identified by normocytic normochromic anemia, lymphocytosis with lymphoblasts, and thrombocytopenia, confirmed by bone marrow analysis. Diagnosis involves clinical and laboratory tests. Treatment includes chemotherapy and supportive care, with a median survival of months to a year. The aim of this study was to report a case of extreme lymphocytosis in a dog suggestive of acute lymphoblastic leukemia. Case: A mixed-breed dog, male, 13.4 kg, 8 years old, was treated at the Veterinary Hospital of UFMT, Cuiabá-MT, with abdominal distension, apathy, and hyporexia. Ultrasound showed hepatosplenomegaly and nodules in the spleen and liver. Physical examination revealed pale mucous membranes, lymphadenomegaly, distended abdomen, normothermia, normohydration, and normal cardiopulmonary auscultation. The complete blood count indicated normocytic normochromic non-regenerative anemia (VG 13%), extreme leukocytosis (160.5 x 10³/µl) due to lymphocytosis (136.43 x 10³/µl), thrombocytopenia (168 x 10³/µl), and Ehrlichia sp. morulae. Serum biochemistry showed hypoalbuminemia (2.5 g/dL), ALT (1,159 U/L), ALP (869 U/L), and normal creatinine. Thoracic radiography revealed a slight increase in volume in the cranial mediastinum. Hospitalization and blood transfusion were recommended but not authorized. Home treatment with doxycycline and vitamins was prescribed. Three days later, the dog returned with severe anorexia and apathy, accepting hospitalization. New tests showed worsening anemia (VG 10%) and increased leukocytosis (201.0 x 10³/µl). A myelogram suggested acute lymphoblastic leukemia. After transfusion and supportive treatment, there was clinical improvement. Referred to an oncologist, the dog died seven days after the last visit. Discussion: The case dog with acute lymphoblastic leukemia (ALL), characterized by uncontrolled proliferation of lymphoblasts. Clinical and laboratory findings included hepatosplenomegaly, normocytic normochromic anemia, extreme leukocytosis with lymphocytosis, thrombocytopenia, and comorbidity with Ehrlichia sp. Organ infiltration caused abdominal distension, apathy, and hyporexia. Bone marrow suppression led to anemia and thrombocytopenia. ALL, a rare and aggressive disease, presents with nonspecific clinics signs like lethargy, anorexia, and hepatosplenomegaly. Definitive diagnosis requires bone marrow aspiration and cytology, while immunophenotyping and PCR tests help differentiate leukemia types. Standard treatment includes aggressive chemotherapy, such as the CHOP protocol. Initial treatment response may be positive, but relapse rates are high, and median survival is short. The case illustrates the challenges in diagnosing and treating ALL, highlighting the importance of early diagnosis and aggressive management.