Ann Hepatobiliary Pancreat Surg.  2020 May;24(2):234-238. 10.14701/ahbps.2020.24.2.234.

Seeking the unseen: Localization and surgery for an occult sporadic insulinoma

  • 1Division of HPB Surgery, Department of Surgery, Faculty of Medicine, University of Colombo
  • 2The University Surgical Unit, The National Hospital of Sri Lanka
  • 3Departments of Endocrinology and Diabetes, The National Hospital of Sri Lanka, Colombo, Sri Lanka
  • 4Departments of Interventional Radiology, The National Hospital of Sri Lanka, Colombo, Sri Lanka


Insulinomas are rare pancreatic neuroendocrine tumours and the commonest cause for endogenous hyperinsulinaemic hypoglycemia. Small tumours are not easily detected by conventional cross-sectional imaging making localization prior to surgical removal a challenge. Selective arterial calcium stimulation is an invaluable adjunct to localization in such circumstances. This is further supplemented by intraoperative ultrasonography. A 39-year-old male was referred with features of Whipple’s triad of 10 months duration. Clinical and biochemical evaluation including C-peptide and serum insulin levels during supervised hypoglycemia concluded endogenous hyperinsulinaemia as the underlying aetiology. Contrast CT and MRI of the abdomen failed to localize the tumour. Selective arterial calcium stimulation localized the lesion in distal pancreas. During the surgery, tumour was further localized to the tail of the pancreas using intraoperative ultrasonography and enucleated. Histology confirmed an insulinoma and patient made an unremarkable recovery and was well more than a year after the surgery.


Insulinoma; Selective arterial calcium stimulation; Enucleation


  • Fig. 1 CECT abdomen showing normal pancreas.

  • Fig. 2 Selective arterial calcium stimulation; (A) Catheter in hepatic vein, (B) Superior mesenteric artery, (C) Splenic artery.

  • Fig. 3 Insulin levels of arterial territories at selective arterial calcium stimulation test.

  • Fig. 4 Insulinoma visualized with intraoperative US combined with Doppler.

  • Fig. 5 Intra-operative findings; (A) Insulinoma at the tail of pancreas near splenic hilum, (B) pancreas, (C) Spleen, (D) surgical specimen of enucleated insulinoma.


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