A 40-year-old woman presents with recurrent episodes of confusion, sweating and palpitations relieved by eating. Biochemistry during a symptomatic episode shows hypoglycemia with inappropriately high serum insulin and negative sulfonylurea screen. Imaging localizes a 1.5 cm pancreatic tail lesion. The most likely diagnosis and its association are:
- A Insulinoma, associated with MEN1 in up to 8% of cases, over 90% benign ✓
- B Gastrinoma, associated with MEN1 in about 25% of cases
- C VIPoma, sporadic in nearly all cases and usually malignant
- D Glucagonoma, associated with necrolytic migratory erythema and diabetes
Correct answer: A. Insulinoma, associated with MEN1 in up to 8% of cases, over 90% benign
Explanation
The clinical picture is Whipple's triad of hypoglycemic symptoms, biochemical hypoglycemia, and relief with glucose administration, pointing to insulinoma, the most common functioning pancreatic neuroendocrine tumor. Insulinomas are usually solitary, small, intrapancreatic, and more than 90% are benign; a minority occur as part of MEN1. Gastrinoma causes Zollinger-Ellison syndrome, VIPoma causes watery diarrhea-hypokalemia-achlorhydria, and glucagonoma causes the rash and diabetes listed in option D, none matching this patient's hypoglycemia.
Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.