A rare case of ectopic antidiuretic hormone-producing pancreatic adenocarcinoma: New diagnostic approach

Abstract

Received for publication May 8, 1995; Accepted for publication January 18, 1996 Reprint requests should be addressed to Dr. Kazumi Iino, the Second Division, Department of Medicine, Hamamatsu University School of Medicine, 3600 Handa-cho, Hamamatsu, 431-31 We describe a 73-year-old man with the syndrome of inappropriate antidiuretic hormone secretion (SIADH) due to an ectopic ADH-producing pancreatic adenocarcinoma. His laboratory findings showed marked hyponatremia, and the water load test showed uncontrolled ADH secretion. The imaging studies revealed pancreatic body cancer. Histological examination revealed an adenocarcinoma of the pancreas, which was positive for ADH immuno-staining. The ADH in the tumor extract was 53.3 pg/g wet weight. In attempt to diagnose ADH-production from the tumor, the ADH in his pancreatic juice was measured and found to be 2.1 pg/ml. We conclude that it is valid to measure the ADH in pancreatic juice to diagnose ectopic ADH production by tumors.