Malignant insulinoma in ectopic pancreatic tissue.

Background: Both ectopic pancreatic tissue and malignant insulinoma are rare. We encountered the combination of these rare entities in a patient demonstrating hypoglycemic symptoms.

Method: A patient with episodic hypoglycemia, non-suppressed serum insulin levels, positive fasting test and a positive localization on both ultrasound and somatostatin receptor scintigraphy by (111)I-labelled octreotide, was operated and investigated.

Results: (111)I-labelled octreotide-guided surgery was performed and a tumor adjacent to the ligament of Treitz was extirpated. Follow-up was uneventful. Histopathology revealed a malignant insulinoma. The patient is currently under close surveillance.

Conclusion: The rare combination of an insulinoma in ectopic pancreatic tissue, where the usual diagnostic endoscopic ultrasound revealed an extrapancreatic mass, is described. This was followed by a positive somatostatin receptor scintigraphy, enabling both radio-guided surgery and future treatment of developing recurrent disease or metastases.