Labrador Retrievers with elevated hepatic
copper levels have been reported; however, it is unclear whether primary
copper-associated
hepatitis occurs in this breed. The objective of this study was to determine whether
copper-associated
hepatitis could be identified in Labradors by reviewing cases from the Diagnostic Center for Population and Animal Health, Michigan State University. Sixteen Labrador Retrievers (3 male, 12 female, and 1 of undetermined sex) between 4 and 11 years old, had multifocal and coalescing, centrilobular
hepatitis characterized by macrophages with abundant intracytoplasmic
copper and
hemosiderin. Other lesions included multifocal, centrilobular and random, pigmented
granulomas, hepatocellular
necrosis,
intrahepatic cholestasis, centrilobular or bridging
fibrosis, and occasionally, pseudolobule formation. In
rhodanine-stained sections,
copper was concentrated in the cytoplasm of centrilobular and midzonal hepatocytes and in macrophages, which is consistent with
copper-associated
hepatitis. In 12 of the dogs, quantitative liver
copper levels were available, and in all but 2 dogs the levels were greater than 2,000 parts per million dry weight (ppm dw). One dog had a liver
copper level of 1,990 ppm dw and one dog with advanced
hepatic cirrhosis had a level of 1,490 ppm dw. The findings suggest that primary
copper-associated
hepatitis likely occurs in Labrador Retrievers.