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