Spectrum of functioning islet cell tumor on multislice computed tomography: experience on 70 patients.
OBJECTIVE
To review experience in preoperative detection of islet cell tumors using multislice computed tomography (MSCT) and summarize various imaging features of functioning islet cell tumors on enhanced MSCT.


METHODS
Seventy patients with clinical or pathological diagnosis of functioning pancreatic islet cell tumor between October 2003 and February 2007 were included in this retrospective study. Seventy-four enhanced MSCT scans in these patients were identified. All MSCT scans were interpreted by two experienced radiologists by consensus interpretation. Surgery and pathology reports were used to confirm the diagnosis, localization, and size of tumors.


RESULTS
Totally, 73 functioning islet cell tumors including 65 benign insulinomas, 2 benign glucagonomas, 3 malignant insulinomas, and 3 malignant glucagonomas were pathologically diagnosed. Tumors in only two cases were not found by MSCT. In 67 benign lesions, 32 showed typical enhancement style, 21 showed prolonged enhancement in portal venous phase, 4 showed delayed enhancement, 4 had iso-dense enhancement with normal pancreatic parenchyma, 2 had no enhancement at all in arterial phase and portal venous phase, and 4 had inhomogeneous enhancement with necrosis or cyst-formation. Patchy or spotty calcifications were found in 3 of the 67 tumors. In 6 malignant islet cell tumors, vessel invasion (2/6) and bowel invasion (1/6) were seen. Different enhancement patterns were shown. All hepatic metastases showed hyper-enhancement during their arterial phase.


CONCLUSIONS
Pancreatic islet cell tumor may display a wide spectrum of presentations in MSCT. Tumors with unusual appearances often present as diagnostic challenges. Non-contrast and post-contrast multiphase scans are recommended for the localization of functioning islet cell tumors.
Xue
Hua-dan
HD
Department of Radiology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100730.
Liu
Wei
W
Sun
Hao
H
Merges
Reto
R
Wang
Xuan
X
Zhang
Xiao-na
XN
Wang
Yun
Y
Zhao
Wen-min
WM
Chen
Jiu-hong
JH
Jin
Zheng-yu
ZY
D000293:Adolescent; D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D007515:Islets of Langerhans / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D010190:Pancreatic Neoplasms / Q000145:classification / Q000000981:diagnostic imaging*; D014057:Tomography, X-Ray Computed / Q000379:methods*