Pancreatic islet cell carcinoma with hypercalcemia and hypergastrinemia: response to streptozotocin

A patient with metastatic islet cell carcinoma of the pancreas, recurrent peptic ulcer disease, and hypergastrinemia (Zollinger-Ellison syndrome) developed symptomatic hypercalcemia and renal insufficiency; she was treated with streptozotocin after parathyroidectomy failed to control her hypercalcemia. Shortly after somewhat less than the usual recommended dose of streptozotocin was administered, the serum calcium concentration fell to near normal with complete resolution of symptoms. Seven months after therapy, mild hypocalcemia, consistent with her degree of renal impairment was noted. However, mild hypercalcemia recurred 13 months after therapy. Shortly after streptozotocin therapy, the mean serum gastrin concentration fell to near normal with radiographic disappearance of the anastomotic ulcer. At 7 and 13 months after therapy, serum gastrin levels were normal. Streptozotocin therapy was accomplished without major complications; specifically, without a detrimental effect on the creatinine clearance. Thus, although hypercalcemia in patients with pancreatic islet cell tumors is often due to associated primary hyperparathyroidism, in some patients it may be due to secretion of a hypercalcemic substance from the tumor and may respond to streptozotocin. Similarly, hypergastrinemia in patients with islet cell tumors may also respond to streptozotocin.