Primary hepatic tumours in cattle. A classification of 66 cases.

A study of 66 primary hepatic tumours was carried out on cattle. These consisted almost entirely of adult females. Fifty hepatocellular tumours (10 adenomas and 40 carcinomas), 10 cholangiocellular tumours (three adenomas and seven carcinomas), two cavernous haemangiomas, two haemangioendothelial sarcomas, one fibroma and one Schwannoma were diagnosed. The 50 hepatocellular tumours were classified into adenomas (20 per cent) and carcinomas (80 per cent), both prevalent in the solitary macronodular form. The hepatocellular carcinomas were divided into six groups based on their distinctive histological arrangement and the morphology of the neoplastic cells: trabecular (55 per cent), pseudoglandular (10 per cent), solid (12 per cent), scirrhous (12 per cent), pleomorphic (7 per cent) and fibrolamellar (2 per cent). Twenty-seven of 50 hepatocellular tumours (54 per cent) were associated with features of blood-filled lakes resembling telangiectasis within the neoplastic tissue. Metastasis was uncommon (10 per cent of hepatocellular carcinomas) and grading according to Edmondson's system (1958) showed a low level of anaplasia in most carcinomas (55 per cent). An association with cirrhosis was never found.