LOCALIZATION OF NEUROENDOCRINE TUMORS OF THE UPPER GASTROINTESTINAL-TRACT

In order to localise neuroendocrine tumours of the foregut type (that is, of the stomach, duodenum, and pancreas), 18 patients were studied prospectively by endoscopic ultrasonography, computed tomography, tran sabdominal ultrasonography, magnetic resonance imaging, and somatostat in receptor scintigraphy. These 18 patients had a total of 25 primary tumour lesions which were verified histologically in tissue obtained b y surgery or by ultrasound or endoscopy guided biopsy. Tumours were fo und in the stomach (n=1), duodenum (n=6), pancreas (n=17), and liver ( n=1). Endoscopic ultrasonography had the highest sensitivity for tumou r detection, followed by somatostatin receptor scintigraphy, computed tomography, transabdominal ultrasonography, and magnetic resonance ima ging (88%, 52%, 36%, 32%, and 24% respectively). Endoscopic ultrasonog raphy was especially sensitive in tumours smaller than 2 cm in diamete r (88% v somatostatin receptor scintigraphy 35%; computed tomography 1 2%; transabdominal ultrasonography 6%; and magnetic resonance imaging 0%). Of 17 tumours located in the pancreas, endoscopic ultrasonography showed a sensitivity of 94% (somatostatin receptor scintigraphy 47%; computed tomography 47%; transabdominal ultrasonography 41%; and magne tic resonance imaging 29%). Of eight extrapancreatic tumours, six were identified by endoscopic ultrasonography, five by somatostatin recept or scintigraphy, and only one by computed tomography, transabdominal u ltrasonography, and magnetic resonance imaging. One neuroendocrine tum our that was not detected by endoscopic ultrasonography was correctly identified by somatostatin receptor scintigraphy. Endoscopic ultrasoun d allowed correct determination of the tumour size and tumour spread i nto parapancreatic structures, especially the large vessels (T stage), in all 14 patients operated upon. The lymph node stage (N stage) was correctly determined in 10 of these 14 patients. In summary, endoscopi c ultrasonography and somatostatin receptor scintigraphy were the most sensitive imaging methods for the localisation of these tumours and s hould be used as early diagnostic procedures to accurately stage neuro endocrine tumours of the foregut type.