Prospective Evaluation of Imaging Procedures for the Detection of Pancreaticoduodenal Endocrine Tumors in Patients with Multiple Endocrine Neoplasia Type 1

Early identification of pancreaticoduodenal endocrine tumors (PETs) in multiple endocrine neoplasia type 1 (MEN-1) is mandatory, because these tumors represent the most common cause of death within the syndrome. The diagnostic value of imaging procedures has therefore been evaluated in a prospective observational study. Between December 1997 and June 2003 twenty-two MEN-1 patients with genetically confirmed disease were followed for PETs using a standardized screening program with serum hormone measurements, endoscopic ultrasonography (EUS), computed tomography (CT), and somatostatin-receptor scintigraphy (SRS). Results could be validated by surgery and histopathology in 13 patients during 18 operations. In 12 asymptomatic patients with tumors measuring 10 mm or less, who have not yet undergone operation, PETs were detected by EUS in 12/12, by CT in 1/12, and by SRS in 2/11 cases. In 13 patients who have undergone surgical exploration EUS, CT, and SRS were true positive in 12 of 16, 7 of 13, and 12 of 17 cases, respectively, although the number of tumors detected by each imaging procedure alone was lower than the number detected intraoperatively and histopathologically in almost every case. A solitary liver metastasis in one patient and a nonfunctioning PET recurrence in another were identified only by SRS. Endoscopic untrasonography is the most sensitive imaging procedure for the detection of small (≤ 10 mm) PETs in MEN-1, whereas SRS is the procedure of choice for the identification of metastases of MEN-1 PETs—i.e., for staging. Detection of PETs at an early stage by an aggressive screening program using EUS may lead to prompt surgical intervention and improved prognosis of MEN-1 PETs.