Insulinoma

Case contributed by Dr J. Ray Ballinger

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

Age: 30 years
Gender: Female
CT

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. 

MRI

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.

DSA (angiography)

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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Case information

rID: 23627
Published: 28th Jun 2013
Last edited: 18th Sep 2019
Inclusion in quiz mode: Excluded

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