Comparison of liver cytology and biopsy diagnoses in dogs and cats: 56 cases.

The results of liver cytology and corresponding biopsy specimens submitted to the Pathology Department at Angell Memorial Animal Hospital during 1998 were retrospectively reviewed to objectively assess the diagnostic value of liver cytology. A "corresponding" biopsy was defined as a biopsy specimen obtained within 1 day of the cytology specimen. Fifty-six cases were reviewed, including 25 from dogs and 31 from cats. Results were in complete agreement in 34 cases, in partial agreement in 11 cases, and in disagreement in 11 cases. Agreement occurred most often in cases of fatty change (10 cases) and neoplasia (7 cases of lymphoma and 3 cases of epithelial tumor). Disagreement was most common in cases of hepatitis (6 cases) in which inflammation was not seen in cytologic specimens. Other causes for disagreement included fibrosis (2 cases), and 1 case each of amyloidosis, hemangiosarcoma, and lymphoma. Three cytologic specimens were considered suggestive of hepatitis because of leukocytosis in the background, although clinicians were advised to compare cytologic observation to CBC results. Cytologic evaluation of the liver was useful for determining disease processes, especially when disease distribution was diffuse.