The histogenesis of hepatoma occurring spontaneously in a strain of sand rats (Psammomys obesus).

Spontaneous hepatomas and hepatic preneoplastic changes were observed in sand rats (Psammomys obesus) from two colonies. Both colonies originated from 10 sand rats captured in the Judean desert in 1969. At the age of 6 months, and increasing in multiplicity with advancing age, histologic examination revealed nodules containing hepatocytes characterized by hyperbasophilia, accumulation of glycogen, eosinophilic cytoplasm, or a mixture of these cells. In animals over 25 months old hepatocellular carcinoma was diagnosed. The histologic changes described here were reported to be characteristic of chemical hepatomagenesis in rats. No external chemical carcinogen could be demonstrated in our animal colonies, and a hereditary predisposition to tumor formation is presumed. Identity of hepatic carcinogenesis, irrespective of etiology in distantly related rodents, ie, the laboratory rat and the sand rat, which in reality is a gerbil, supports the assumption of the existence of a general law governing hepatic carcinogenesis.