In 1981-1997 at the Third Medical Clinic 52 patients with confirmed organic hyperinsulinism were treated. Forty-three were operated and the remaining nine were treated conservatively. An insulinoma was removed surgically in 35 patients, in one female microadenomatosis was detected. The operation was successful in 84%, while topographic preoperative examination aroused suspicion of a focus (i.e. insulinoma) only in 49% of the operated patients. A total of 11 patients (four after surgery and seven not operated) were treated successfully with diazoxide, in nine patients this treatment is still administered. According to the response to diazoxide it is possible to differentiate "responsive" and "non-responsive" insulinomas. Pharmacological treatment is thus justified only in the first group of patients. Surgically and pharmacologically treated patients have no signs of hyperinsulinism. The authors experience suggests that surgical treatment is indicated when the diagnosis is unequivocal even when the topographic finding of imaging methods is negative, as in 35% of operated patients the insulinoma was found only on operation.

Keywords: Adolescent; Adult; Aged; Aged, 80 and over; Female; Humans; Hyperinsulinism /etiology/; Insulinoma /complications/; Male; Middle Aged; Pancreatic Neoplasms /complications/