A case of occult insulinoma localized by pancreatic dynamic enhanced spiral CT

Figure 1 Clinical images related to this case and linear analysis of pancreatic dynamic enhanced spiral CT. A: Negative result of abdominal enhanced spiral CT; B: We used intraoperative ultrasonography to detect the tumor and to determine the location relationship between the tumor and the main pancreatic duct. Fortunately, the tumor (green arrow) did not adjoin the main pancreatic duct. Therefore, we performed simple tumor resection; C: The insulinoma (green circle) (1.4 cm × 1.4 cm × 1.2 cm) was resected; D: Microscopic image of the insulinoma after immunostaining (× 400); E: Enhancement value of the pancreas and insulinoma at each time point after the onset of contrast material injection. The enhancement value peak of the tumor appeared at 65 s. As the interval of tumor-to-pancreas contrast was not obvious (mostly it is < 20 HU), the insulinoma was occult and difficult to find.

Figure 2 Images of pancreatic dynamic enhanced spiral CT showed the localization of the insulinoma (white arrows). It was in the body of the pancreas (adjoining the neck). The tumor started to enhance from 45 s after the onset of contrast material injection, and could be seen until 85 s. As the contrast between the insulinoma and the pancreas was not obvious, the tumor was difficult to find by other conventional imaging techniques.