[Insulinoma of the pancreas--difficulties with imaging].

We present a case of 29-year old man in whom despite the lack of finding tumor in USG and CT surgical intervention was performed and insulinoma of the pancreas was excised. Insulinoma was diagnosed on the basis of clinical picture (Whipple's triade) that was reassured by positive fast test. The fast was terminated at 11 and half hours because of neuroglycopenic symptoms with serum glucose and insulin levels 2.0 mmol/l (36 mg/dl) and 11.07 microU/ml respectively, which established the diagnosis. Laparotomy was performed, during which the tumor was palpated and seen in ultrasonography in the head of pancreas. The tumor of 12 mm diameter was excised. Histopathological examination revealed benign insulinoma. After surgery the symptoms alleviated completely. The patient with proper glucose levels was discharged in good health. The case supports high usefulness of intraoperative ultrasonography and surgeon's palpation.