Selective Calcification of Pancreatic Islets of Langerhans: An Unusual Association with Hypercalcemia and Diabetes Mellitus

An unusual and extensive calcification of islets of Langerhans was found at autopsy in a man, 58 years old, who developed myeloma and, subsequently, hypercalcemia and diabetes. Although the islet cell calcification appears to be related to the hypercalcemia, the pathogenesis of the calcification is not clear, as primary metastatic calcification of pancreatic islets due to hypercalcemia does not occur. In support of this, a retrospective study of pancreatic tissue from 52 hypercalcemic patients with parathyroid adenoma and 34 patients with multiple myeloma, who frequently have hypercalcemia, did not reveal islet calcification. The islet calcification is ascribed to primary islet cell degeneration and necrosis, with hypercalcemia playing an augmenting but crucial role. It is considered that the combination of islet degeneration and calcification resulted in the diabetic state.