Insulinomas associated with multiple endocrine neoplasia type I: the need for a different surgical approach

Insulinomas are usually solitary (greater than 90%) benign pancreatic tumors readily cured by enucleation or resection. To determine whether the 4% of insulinomas associated with multiple endocrine neoplasia type 1 (MEN-I) require a different surgical approach, we analyzed our experience in seven patients with MEN-I insulinomas treated during the past 28 years at the University of California, San Francisco, and 53 patients reported in the English literature. We found: (1) MEN-I insulinomas were associated with an antecedent history of other endocrinopathy or a family history of MEN-I in six of our seven patients, allowing preoperative identification of these patients. (2) All seven of our patients had hyperparathyroidism and four had pituitary tumors. Overall 83.6% of patients had hyperparathyroidism and 45.4% had pituitary tumors. (3) In our patients, MEN-I insulinomas were usually multiple (median 3; range 1 to 14). Overall, 76.3% of patients had multiple islet cell tumors. (4) Distal subtotal pancreatectomy with enucleation of any tumors identified in the head of the gland was done in five of our patients. Four are now normoglycemic and one is diabetic. Enucleation alone failed in one patient. The seventh patient was diagnosed at autopsy. Because the diagnosis of MEN-I can generally be made, preoperative strategy can address the unique pathologic features of insulinomas associated with MEN-I. The tumors are usually multiple, so local resection will fail. We recommend subtotal pancreatectomy in addition to enucleation of tumors in the head of the pancreas.