Background/aims: Pancreatic neuroendocrine tumors (PNET) are rare and manifest as functioning tumor (FT) or non-functioning tumor (NFT). Although malignant changes are observed in some cases, its prognosis is better than pancreatic cancer. We evaluated clinicoradiologic features and prognosis of FT and NFT. In addition, we tried to find the predictive factors for the recurrence of NFT after resection.
Methods: Between October 1994 and June 2004, we retrospectively evaluated the clinicopathologic features and prognosis of 12 cases of FT and 31 cases of NFT diagnosed by surgical pathology at single medical center in Korea.
Results: PNET included 6 insulinomas, 4 gastrinomas, 1 glucagonoma, 1 somatostatinoma and 31 NFT. The major clinical manifestations were neuroglycopenic symptoms (100%) in insulinoma, abdominal ulcer symptoms (75%) in gastrinoma, dermatitis (100%) in glucagonoma, steatorrhea (100%) in somatostatinoma, and abdominal discomfort or pain (45%) in NFT. NFT was located more proximally when compared to FT (p=0.023). NFT showed more malignant (64.5%) behavior compared to FT (41.7%) despite the lack of statistical significance. Curative resections were done without postoperative death in 38 cases. Six cases of NFT (21.4%) and 1 case of FT (10%) recurred with an average of 26.5 months. In the recurrent NFT, the findings of diabetes mellitus (p=0.010), abnormal pancreatic duct (p=0.026), Whipple's operation (p=0.013) and tumor emboli (p=0.03) were more common than in non-recurrent NFT.
Conclusions: FT and NFT showed different clinicoradiologic features. In addition, NFT should be monitored more carefully because of frequent recurrence.