Centrilobular distribution of diethylnitrosamine-induced hepatocellular foci in the mouse.

Hepatocellular foci, considered possible precursors of trabecular hepatocellular carcinomas, were induced after 10 weeks by injecting male B6C3 F1 mice with diethylnitrosamine, 5 mg/kg, when they were 15 days old. The locations of 41 of the foci with diameters between 80 and 112 microns were determined in serial sections of blocks of liver from five mice. The average distance between centers of foci and closest hepatic vein branches (143 microns) was 40% less than that between randomly selected points and veins (243 microns). The centrilobular distribution of the foci might have facilitated the infiltration of hepatic vein branches, which was a prominent feature in animals killed after 20 weeks. This is the first stereologic study documenting the nonrandom distribution of neoplastic or preneoplastic foci in the rodent liver.