DIAGNOSIS AND TREATMENT OF INSULIN-SECRETING PANCREATIC-ISLET CELL TUMORS IN FERRETS - 57 CASES (1988-1994)

Objective-To evaluate clinical, laboratory, radiographic, ultrasonogra phic, surgical, and histologic findings in ferrets with insulinoma and to determine their long-term outcome. Design-Retrospective study. Ani mals-57 ferrets with a histopathologic diagnosis of pancreatic islet c ell tumor. Procedure-Medical records of ferrets with pancreatic islet cell tumors were reviewed. Results-Lethargy, weakness, and collapse we re the most common clinical signs. All ferrets had hypoglycemia, and h yperinsulinemia was documented in 39 of 47 (83%) ferrets. Ultrasonogra phic examination of the abdomen revealed pancreatic nodules in 5 of 23 ferrets. Surgical treatment was performed in 50 ferrets, 3 were treat ed by medical management alone, and 4 did not have treatment. At the t ime of surgery, 1 pancreatic nodule was found in 13 (26%) ferrets and multiple nodules were found in 37 (74%) ferrets. Pancreatic carcinoma alone was found in 34 ferrets, whereas a combination of carcinoma and either hyperplasia or adenoma was found in 23 ferrets; 4 ferrets had m etastasis to regional lymph nodes or liver. In 26 (53%) ferrets, hypog lycemia persisted after surgery, necessitating medical treatment with prednisone, diazoxide, or both. Sixteen (33%) ferrets had redevelopmen t of hypoglycemia at 1 to 23.5 months (median, 10.6 months) after surg ery. Only 7 of the 50 (14%) ferrets remained euglycemic after surgery. Clinical Implications-In ferrets, surgical removal of insulin-secreti ng pancreatic islet cell tumors is recommended as definitive treatment ; however, multiple pancreatic nodules are common, making complete exc ision of all tumor tissue difficult. Persistent hypoglycemia after sur gical treatment indicates that lifelong medical management with predni sone or diazoxide or both may be necessary in many ferrets. Finally, b ecause the insulin-secreting tumors are malignant, long-term cure and survival are not likely.