Presentation
Presented 3 days after a 20 minute episode of dizziness, blurred vision and weakness. A non-fasting blood glucose level of 45 mg/dL was discovered.
Patient Data
Note: This case has been tagged as "legacy" as it no longer meets image preparation and/or other case publication guidelines.
The two CT images were obtained pre-contrast and arterial phase and portal phase. The arterial phase shows a subtle enhancing mass in the tail of the pancreas measuring about 2 cm in diameter.
The MRI T2-weighted fat-suppressed images show the mass in the tail of the pancreas to be of increased signal compared to the remainder of the pancreas.
An incidental accessory spleen is noted in the splenic hilum cephalad to the tail of the pancreas.
Calcium arterial stimulation with venous sampling was performed to confirm the localization of the insulinoma in the tail of the pancreas. A calcium solution was injected at different times into the splenic, hepatic and superior mesenteric arteries with sampling from the right hepatic vein for insulin levels several times over two minutes each.
Case Discussion
The patient went on to have a resection. At surgery, a 2.2 x 1.7 x 1.3 cm diameter nodule was removed.
Histology
Sections show a pseudoencapsulated tumor composed of islet cells with a benign appearance, consistent with an insulinoma.
Discussion
Insulinomas are neuroendocrine tumors that arise from B-type islet cells in the pancreas and are rarely larger than 2 cm in diameter. Patients present with CNS and vasomotor symptoms resulting from spontaneous hypoglycemia. Insulinomas are hypervascular and so are dense on enhanced CT. On MRI they tend to be bright on T2-weighted sequences and low-density on T1- weighted sequences.
Other neuroendocrine tumors found in the pancreas include:
- gastrinoma
- glucagonoma
- VIPoma
- PPoma
- somatostatinoma
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