Insulin-secreting tumor: diagnosis and medical and surgical management in 55 dogs.

Insulin-secreting tumor of the pancreas was diagnosed in 55 dogs. Diagnosis was based mainly on the increase of serum insulin concentrations in the presence of hypoglycemia. The use of the amended insulin/glucose ratio to diagnose the tumor, although providing less false-negative results than did increased serum insulin concentrations alone, appeared less specific and gave false-positive results in dogs without insulin-secreting tumors. Management of the disease included surgical intervention alone (26 dogs), surgery plus medical management with diazoxide (14 dogs), and medical management with diazoxide alone (4 dogs). Eleven dogs were euthanatized at the time of diagnosis. Diazoxide therapy controlled hypoglycemia in about 70% of the dogs.