Diagnostic and treatment difficulties in insulinomas

Background: Neuroendocrine tumors of the pancreas (NTP) comprise a unique and relatively rare group of tumors, of which gastrinoma and insulinoma are the most common types. Insulinomas tend to be small, solitary and benign, with surgical resection curable in most cases. Introduction: Insulinomas are localized preoperatively using conventional imaging studies as transabdominal ultrasonography (US), computed tomography (CT), and/or magnetic resonance imaging (MRI). Purpose: Endoscopic ultrasound (EUS) is a valuable tool in the diagnosis of insulinomas. Goals & methods: We performed a retrospective study on 21 patients with insulinoma (6 male and 15 female, 25 to 73 years of age), who were hospitalized and operated on between 2003 and 2012 at “Dr. Carol Davila” Central Military Emergency University Hospital, Bucharest. Results: US view was positive in 10% of patients (2 of 20), that presented proximal location. The sensitivity of CT was unsatisfactory, 21.05% (4 positive results of 19). CT failed to detect liver metastases, but identified nodal metastasis in one patient. MRI was performed in 18 patients and was diagnostic in 11 of them, recording a detection sensitivity of 61.11%, including infracentimetric tumor size. EUS has a high resolution which allows detection of lesions with very small diameter is safe and minimally invasive. EUS was performed in all patients, being able to identify formations in 17, was inconclusive in 3, showing a diagnosis sensitivity of 81%. Liver metastases were demonstrated in 3 patients, one by US and all 3 by MRI. Conclusions: - CT with intravenous iodinated contrast agent had a poor sensitivity in detecting the primary tumors, was insensitive in detecting liver metastases, but showed metastases in lymph nodes. - MRI has higher sensitivity than CT in detecting primary tumors, including insulinomas with infracentimetric size, and is the imaging test of choice for possible liver metastases. - EUS is the preoperative imaging test of choice.