Midzonal necrosis as a pattern of hepatocellular injury after shock.

Midzonal necrosis is rarely observed in human liver, except in patients with yellow fever. In a retrospective analysis of livers from 1000 consecutively autopsied adult patients, we observed midzonal necrosis in 1.8% of the cases, and in 8% of patients with centrilobular necrosis. All of the affected patients had a history of one or more episodes of hypotension several days before death, and most patients (72%) had a history of congestive heart failure. Although the midzonal pattern of necrosis was always accompanied by centrilobular necrosis, the two patterns were not uniformly observed in the same microscopic fields. In 11 of 18 cases (61%), the midzonal pattern of necrosis appeared to be partially a consequence of centrilobular regeneration of hepatocytes. In 28% of the cases, however, the midzonal pattern of necrosis was primary and associated with selective survival of centrilobular and periportal hepatocytes. We conclude that midzonal hepatocellular necrosis may be observed after hypotension, and toxin- or drug-induced injury need not be implicated in the pathogenesis. This information may be useful in the interpretation of needle biopsy specimens of the liver.