Diagnosis of Insulinoma by Endoscopic Ultrasonography: A Case Report

A 51-year-old woman was hospitalized for episodic loss of consciousness over a one year period. The presence of insulinoma was indicated clinically and biochemically; but conventional ultrasonography (US) and computed tomography (CT) failed to reveal a tumor, thus surgical intervention was deferred. The patient was readmitted 3 years later with an increasing frequency of hypoglycemic episodes. Conventional US showed a suspicious, small, ill-defined hypoechoic mass in the pancreatic head. CT and selective angiography revealed equivocal results. Endoscopic ultrasonography (EUS) clearly demostrated a well-demarcated, echo-free mass, measuring 2×0.8cm, in the head of the pancreas. Insulinoma was confirmed by surgical pathologic examination. These results indicate that the EUS provides a distinct advantage in pre-operative visualization of insulinomas.