Contrast-enhanced ultrasonographic detection of small pancreatic insulinoma.

Endocrine tumors of the pancreas originate from multipotential stem cells that have retained the capacity to proliferate and differentiate themselves in the various cellular lines that make up this group of neoplasms. Insulinomas represent the most frequently found functioning endocrine tumors of the pancreas and are benign in most cases (85%-99%), are single (93%-98%), and have diameters of less than 2.5 cm. When malignant, their diameters are generally greater than 3 cm, and about one third of these have metastases at the moment of diagnosis. They appear early with signs and symptoms linked to hypoglycemia due to the hypersecretion of insulin; they are almost exclusively located at the pancreatic level with no preferential sites. Preoperative ultrasonographic detection of insulinomas is generally difficult but possible in 25% to 60% of cases.3 The main difficulty in detecting a pancreatic insulinoma lies in the organ's anatomic structure and the tumor's small dimensions at clinical appearance. The use of second-generation contrast-enhanced imaging can increase the capacity to detect pancreatic insulinomas in preoperative ultrasonography, as the following case confirms.