Insulinomas account for 50% of all islet-cell tumors and are the most common islet-cell tumor subtype.
1) Gastrinomas are the second most common islet-cell tumor, with approximately 25% associated with multiple endocrine neoplasia (MEN-1).
The typical appearance of a pancreatic islet-cell tumor is a well-circumscribed, solitary, hypervascular mass (Figure 4).
While rare, these can be mistaken for a pancreatic islet-cell tumor due to similar enhancement characteristics.
22 In our experience in one very rare instance, a pancreatic islet-cell tumor presented with a purely cystic appearance (Figure 21).
The presence of calcifications is more suggestive of a pancreatic islet-cell tumor and can be helpful in differentiating a lesion from adenocarcinoma of the pancreas.
Once the diagnosis and staging of a pancreatic islet-cell tumor is performed, imaging is helpful in determining the success of surgical treatment and monitoring for signs of recurrence.
Although pancreatic islet-cell tumors account for only 1% to 5% of all pancreatic neoplasms, they represent an important subset of pancreatic neoplasms due to their substantially improved prognosis compared to pancreatic adenocarcinoma.
Ninety-five percent of pancreatic islet-cell tumors are solitary and sporadic.
On the other hand, hyperfunctioning islet-cell tumors (referred to as syndromic islet-cell tumors) manifest much earlier, and at a much smaller size due to symptoms caused by hormonal oversecretion.
Unlike sporadic islet-cell tumors, inherited pancreatic islet-cell tumors are usually multiple in location and most often related to MEN-1.
Pancreatic islet-cell tumors spread first to regional lymph nodes, then to the liver, bone, and rarely, to distant sites such as the lung or brain.