Granulomatous hepatitis in dogs: nine cases (1987-1990).

Granulomatous hepatitis (GH) is an uncommon histopathologic diagnosis in dogs. On the basis of clinical reports, fungal infections appear to be the most common cause of GH in dogs, but many other potential causes have been identified. The medical records and histopathologic findings for 9 dogs with GH were reviewed to identify additional specific causes of GH in dogs. Diseases associated with GH included intestinal lymphangiectasia (n = 2), lymphosarcoma (n = 1), histiocytosis (n = 1), dirofilariasis (n = 1), and histoplasmosis (n = 1). In 1 dog, no other disease process was identified. Of the remaining 2 dogs, 1 had concurrent granulomatous pneumonitis of unknown cause, and the other had periportal hepatitis and temporal muscle wasting. All 9 dogs with GH had clinical evidence of liver disease, such as hepatomegaly, icterus, and ascites, or had high serum alkaline phosphatase and alanine aminotransferase activity. Because of the wide variety of potential causes of GH in dogs, an accurate diagnosis should be sought so that appropriate treatment can be chosen and an accurate prognosis given.