Vanished islets with pancreatitis in acute-onset insulin-dependent diabetes mellitus in an adult.

We report an autopsy case of acute-onset insulin-dependent diabetes mellitus, type I, that occurred in an adult. The patient died 3 days after the clinical onset of diabetes. Hyperglycemia, ketonuria, and hyperamylasemia were observed at admission. The pathologic examination of the pancreas showed a markedly decreased number of islets, and residual islets were small and shrunken. Diffuse inflammatory cell infiltrates, which were found in islets and also in acini, were mainly T lymphocytes. Shrunken islets were composed of insulin cells, glucagon cells, somatostatin cells, and pancreatic polypeptide cells. A decreased number of zymogen granules in acini were prominent [corrected]. This case suggested that pan-pancreatitis, destroying whole islets and acini, can initiate insulin-dependent diabetes mellitus.