Insulinoma: Diagnosis and Surgical Treatment. Retrospective Analysis of 31 Cases

Background: Insulinomas are rare tumors that are usually benign, single and curable by simple surgical excision. They can present problems in diagnosis and localization.

Study Design: Retrospective analysis of patients with insulinoma managed during a 13-year period (1992-2005) at a tertiary-level institution.

Results: 31 patients (mean age 38.4 [SD 13.3] years; 16 men) presented with hypoglycemic symptoms for 4.6 (5.5) years. In 22 (71%) patients, the lesion was successfully localized pre-operatively. Of various pre-operative localization techniques, CT angiography (5/6; 83%), intra-arterial digital subtraction angiography (11/17; 65%), dual-phase CT (8/14; 57%) and conventional MRI (4/13; 31%) had high rates of successful tumor localization. Intra-operative palpation and ultrasonography also had localization success rates (22/30 [76%] and 11/12 [92%], respectively); each identified one lesion that the other procedure did not localize. Of the 30 patients who underwent surgery, 28 had solitary tumor.

Conclusion: Pre-operative investigations to localize insulinoma are helpful despite the availability of intra-operative ultrasound. Dual-phase CT should be the non-invasive investigation of first choice.