Successful preoperative localization of a small pancreatic insulinoma by diffusion-weighted MRI.

CONTEXT Insulinoma is the most common functioning endocrine tumor of the pancreas responsible for fasting hypoglycemia resulting from autonomous insulin hypersecretion. Most insulinomas are small and difficult to localize with conventional imaging. We successfully localized a small insulinoma in our patient using diffusion-weighted magnetic resonance imaging before surgery. CASE REPORT We report the case of a female patient with a clinical suspicion of insulinoma. A preoperative MR with diffusion-weighted imaging was performed and localized a small nodule in the pancreatic tail. Treatment consisted of surgical enucleation. Histologic examination identified a neuroendocrine tumor compatible with an insulinoma. CONCLUSION Diffusion-weighted imaging can be useful in detecting and localizing small insulinomas, especially for those with no hypervascular pattern.