In 1981-2000 at the IIIrd Medical Clinic 60 patients were treated with confirmed organic hyperinsulinism. A surgical operation was indicated in 51 patients. In 42 a localized tumour was removed, in one diffuse adenomatosis was involved. In three of the operated patients a malignant, enddocrinologically active insulinoma was confirmed. Two patients were re-operated on account of a relapse. The remaining 9 patients were treated conservatively from the onset. For localization of the tumour before operation US, CT and angiographic examinations were used. US and angiography were an asset in 25 patients (49 %). In some instances we encountered however on angiography falsely positive findings. US was positive before surgery in 12 patients (23 %), angiography in 21 (41 %) and CT only in 2 (4 %). The insulinoma was detected only on surgery in 14 patients (33 %) of the operated insulinomas. The tumour was found in the head of the pancreas in 13 patients (31 %), in the body of the pancreas in 14 (33 %) and in the tail of the pancreas in 15 (36 %). Surgery was successful in 82 %, while the topographic preoperative examination aroused suspicion of a focus (i.e. insulinoma) only in 49% of the operated patients. A total of 17 patients (8 after surgery and 9 without surgery) were successfully treated with diazoxide, in 9 patients this treatment is still administered. According to the response to diazoxide insulinomas can be divided into „responsive“ and „non-responsive“ ones. Pharmacological treatment is therefore justified only in the first group of patients. Operated and pharmacologically treated patients have no signs of hyperinsulinism. Our experience indicates that a surgical approach is suitable when the diagnosis is unequivocal, even when there is a negative topographic finding of imaging methods as in 33 % of the operated patients the insulinoma was detected only on operation.

        Key words: organic hyperinsulinism - surgical solution - diazoxide