Cytochemical staining for diagnosis of acute myeloid leukemia in a canine

Abstract

Acute myeloid leukemia (AML) is a malignant neoplasm arising from the proliferation of hematopoietic cells in the bone marrow, and is considered uncommon in dogs. Due to this, the objective of this study is to report a case of AML of possible myelomonocytic lineage in a canine, highlighting the importance of performing cytochemical staining on blood smears to obtain a definitive diagnosis. A canine, Rottweiler, male, 10 years old, weighing 25.1kg, was treated with a main complaint of apathy, indisposition, anorexia and adipsia for three days. On physical clinical examination, during auscultation he presented muffled heart sounds, pale mucous membranes and cachexia. The blood count showed the presence of anemia, thrombocytopenia and leukemia. The blasts were greater than 30% in relative count, consistent with acute leukemia. The slides were stained using cytochemistry with periodic acid-Schiff and peroxidase, being compatible with cells of myeloid origin (granulocytic and/or monocytic), obtaining a definitive diagnosis of AML of possible myelomonocytic lineage. An abdominal ultrasound (US) was performed, which showed an image suggestive of neoplasm in the liver and spleen. From fine needle cytology guided by US, material was collected from the liver, which showed leukemic infiltration. The patient died within five days and the necroscopic examination was not authorized by the person responsible. It is concluded that a thorough clinical examination associated with the blood count and cytochemical staining of circulating blasts were crucial for obtaining an early and definitive diagnosis of AML of possible myelomonocytic lineage in the patient in this report.