Wednesday 1 December 2010
It is difficult to predict the malignant nature of an insulinoma on the basis of its histological features.
The current WHO classification criteria for malignant insulinoma involve the presence of metastases, gross invasion, tumor size, percentage of mitoses, proliferative index and vascular invasion.
However, metastases are generally considered the only definitive characteristic of malignancy. Out of all insulinomas, 5%-10% are malignant.
The differential diagnosis between malignant and benign insulinomas is usually very difficult and is based on intraoperative evidence (metastases in the liver, regional nodes or local invasion), whereas in some patients the metastases are frequently found along with the recurrence of a hypoglycemic episode.
It is important to discover alternative ways of estimating the malignant potential of insulinomas and not solely rely on histopathological examination.
The combination of medical and surgical therapeutic approaches must be considered for the treatment of malignant insulinomas.
Intravenous streptozotocin chemotherapy could be administered according to published protocols (500 mg/m2 strep-tozotocin on 5 consecutive days and repeated every 6-8 weeks) and additional chemotherapy could be used according to the stage of the disease.
For prognosis, see "pancreatic endocrine tumors" (PETs).
The malignancy of insulinomas is difficult to be predicted on the basis of their histological features, and the current WHO classification has been re-evaluated.
pancreatic endocrine tumors" (PETs)
Pancreatic insulinoma: current issues and trends. Vaidakis D, Karoubalis J, Pappa T, Piaditis G, Zografos GN. Hepatobiliary Pancreat Dis Int. 2010 Jun;9(3):234-41. PMID: 20525548 [Free]