Cytology Q&A 06

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A six-year-old female spayed DSH cat presented for chronic weight loss and a recent history of vomiting and severe lethargy. Physical examination revealed pale, icteric mucous membranes. The temperature was 38°C (100.4°F) and pulse and respiration rates were slightly increased. Abdominal palpation and radiographs revealed diffuse hepatomegaly. Examination of a peripheral blood smear indicated RBC shape abnormalities including severe acanthocytosis. Abnormal biochemistry values were: AST = 150 U/l (ref. = 2–36 U/l); ALT = 350 U/l (ref. = 6–80 U/l); ALP = 135 U/l (ref. = 2–43 U/l); bilirubin = 68 μmol/l (ref. = 0–3.4 μmol/l). An FNA of the liver was obtained and a smear made (Wright–Giemsa, ×25).

Question	Answer		Article
Explain the abnormal RBC shape and the biochemistry abnormalities.	Acanthocytes are spherical erythrocytes with blunt tipped spicules of different lengths projecting from the surface at irregular intervals. Abnormal amounts of lipid may accumulate in the outer half of the lipid bilayer during liver disease. This causes the membrane to evaginate and form spicules, resulting in acanthocytosis. The mild elevation in ALT and AST suggests minimal hepatic damage. Elevated bilirubin and alkaline phosphatase are indicative of cholestatic liver disease. Even mild elevations of serum ALP are significant in the cat because of the short half-life of the enzyme in this species.		Link to Article
Describe the cytological findings, and give your cytological interpretation.	Several hepatocytes are seen, many of which contain distinct, punctate, clear cytoplasmic vacuoles. The nuclei of many of these hepatocytes are pushed to the periphery due to cytoplasmic vacuoles. Abundant punctate vacuoles are also noted in the background. The cytological interpretation is vacuolar degeneration compatible with hepatic lipidosis.		Link to Article
List the differentials for your diagnosis, and discuss treatment options.	Hepatic lipidosis in cats may be a primary disease or may occur secondary to other metabolic, inflammatory or neoplastic conditions. Approximately 50% of cases are idiopathic. Differentials for secondary hepatic lipidosis include diabetes mellitus, pancreatitis, hyperthyroidism, steroids or neoplasia. The key to successful management of cats with lipidosis, as seen in this case, is early diagnosis and intensive nutritional support. Cats typically require nutritional support for 3–6 weeks with high-protein, calorie-dense food, usually via PEG tubes. Because these cats are already ill and stressed, extreme care must be taken not to cause further stress by force-feeding. Note: An additional photomicrograph is included here for comparison (29b) (Wright–Giemsa, ×100 oil). The multiple small, crisply defined cytoplasmic vacuoles within hepatocytes are characteristic of this condition.		Link to Article