Marked islet amyloid polypeptide-positive amyloid deposition: a possible cause of severely insulin-deficient diabetes mellitus with atrophied exocrine pancreas.

An insulin-deficient 51-year-old man was put on dietary therapy and sulfonylurea (SU). Although there was good glycemic control for 2 years, the fasting blood glucose (FBG) level increased gradually over the subsequent 4-year period, and there was a marked increase in body weight. Secondary failure of SU therapy 20 years after the initial diagnosis led to insulin therapy. The FBG became unstable, and the C-peptide response disappeared. The patient died of nonketotic hyperosmolar coma and pneumonia at the age of 87. At autopsy, the pancreas showed marked atrophy (32 g) with extensive fatty degeneration. Islets replaced by islet amyloid polypeptide (IAPP)-positive amyloid (IAPP-AM) amounted to 77% in the tail, 74% in the body, and 73% in the head of the pancreas. All islets were positive for IAPP-AM throughout the pancreas, except for a pancreatic polypeptide-rich lobe, where none were positive. IAPP-AM-positive islets had also undergone fatty change of the surrounding pancreatic acinar cells. beta-Cells decreased remarkably in number and were displaced to the periphery of the islets by the IAPP-AM deposits. These findings suggest that IAPP-related diabetes could have a progressive course, with secondary oral hypoglycemic agent failure and the subsequent development of severe insulin deficiency similar to that seen in insulin-dependent diabetes mellitus.