Stomatocytosis in a Beagle and Australian Cattle Dog

Abstract

Background: Canine stomatocytosis is a well-recognised rare erythrocyte disorder characterised by non-syndromic forms with selective erythroid involvement, syndromic forms with extra-haematological disease and acquired forms. Objectives: We describe serial clinicopathologic changes in two dogs with stomatocytosis of breeds that are different to those previously reported. Methods: Blood samples were obtained from a twelve-year-old female neutered Australian cattle dog and a twelve-year old male neutered beagle for haematological and biochemical analyses, including morphologic examination of peripheral blood films. Serial clinicopathologic data, including CBCs performed by the referring veterinary surgeons were reviewed. Results: Serial CBC data in both cases reported a variable decrease in RBC numbers commonly associated with a normal haematocrit, macrocytosis, hypochromasia, changes in red cell distribution width parameters including marked histogram abnormalities in volume distribution of the RBC population, and mildly increased or normal reticulocyte counts. Morphologic examination of peripheral blood films identified variable numbers of stomatocytes, knizocytes (Case 1, Day 1, Day 4), mild anisocytosis, mild macrocytosis and mild polychromasia. Conclusions: In both cases, the changes exhibited in the erythrogram raise a suspicion for a RBC membrane disorder with cell volume dysregulation and stomatocytosis although did not appear to cause clinically relevant haemolysis.