MASTOCYTHEMIA IN A FELINE - CASE REPORT (Atena Editora)

Abstract

Mastocytemia is characterized by the presence of circulating mast cells identified in blood smears or buffy coats. It is a rare anomaly reported in only 0.05% to 0.33% of felines and is most commonly associated with visceral mast cell tumors. In dogs, the presence of circulating mast cells is more common and is associated with conditions such as inflammation, regenerative anemia, neoplasms, trauma, necrosis, and tissue injury. Mastocytoma affects about 2% to 15% of felines, with its primary forms being visceral and cutaneous, in addition to a systemic hematopoietic form that affects the liver, bone marrow, and spleen, the latter being the most frequently involved. In this study, we report the presence of mastocytemia found in the blood smear of a 3-year-old male feline patient with no prior history of neoplasia. The patient was referred for clinical care with initial complaints of lethargy, anorexia, and emesis. During physical examination, the patient presented with mild dehydration, slightly pale mucous membranes, coarse lung sounds upon auscultation, a body temperature of 36.6°C, and ultrasonographic examination (US) revealing splenomegaly (measuring 1.46 cm in thickness), nephropathy (renal infarction and hyperechogenicity in the right kidney), enlarged lymph nodes, and a small amount of free fluid. Radiographic examination showed pulmonary opacification and dorsal volume enlargement at the second sternum. Biochemical analysis revealed a slight increase in serum urea level (65.2 mg/dL), and the blood count showed a hematocrit of 21%, thrombocytopenia with 131,000/mm³, 53,850 total leukocytes/mm³, 50% of which were mast cells. The highest absolute circulating mast cell count has been reported in younger cats, similar in age to the patient in question. The literature describes symptoms similar to those observed in this patient. The presence of circulating mast cells in the blood smear of cats without an initial suspicion of neoplasia should always be investigated with the aid of complementary tests such as cytology, histopathology, US, and radiography. Unfortunately, it was not possible to determine the cause of the mastocytemia as the patient died. There are few reports on this condition, so mast cell disease should be further studied in this species, as well as its potential correlation with other pathological conditions.