LIMITED TUMOR INVOLVEMENT FOUND AT MULTIPLE ENDOCRINE NEOPLASIA TYPE-I PANCREATIC EXPLORATION - CAN IT BE PREDICTED BY PREOPERATIVE TUMOR-LOCALIZATION

Radiologically demonstrable pancreatic endocrine tumors are a frequent requirement for exploration in patients with multiple endocrine neopl asia type I (MEN-I). Such delayed intervention is accompanied by a 30% to 50% incidence of pancreatic endocrine metastases. This study explo res biochemical tumor markers and operative findings in relation to pr eoperative pancreatic radiology in 25 MEN-I patients. They underwent p ancreatic surgery with (n = 19) or without (n = 6) radiology, signs of primary tumor and absence of metastases upon conventional examination , including OctreoScan testing (n = 10), Biochemical diagnosis require d an increasing elevation of at least two independent pancreatic tumor markers. Tumor diameters averaged 1.1 cm (0-5 cm) and 0.9 cm (0.2-1.5 cm) in the patients with and without positive preoperative radiology, respectively, These investigations never displayed more than one of t he consistently multiple tumors, and the results were falsely positive in 26%. Preoperatively unidentified regional or hepatic metastases we re found at surgical exploration in 26% of patients with radiologic lo calization and in none of the others, Limited pancreatic tumor involve ment necessitated intraoperative absence of metastases and pancreatic lesions less than or equal to 1 cm in diameter on palpation, intraoper ative ultrasonography, and microscopy. It occurred in 37% and 50% of t he patients with and without radiologic tumor localization, respective ly, The number of positive tumor markers was similar for patients with limited and major disease (2.3 vs. 2.7), whereas four or more such ma rkers were found in all those with malignancies. The mean marker level was higher ill patients with radiologically demonstrable tumors and l ower in those wi;th limited disease, but with a substantial overlap. O ctreoScan testing was negative in all cases with limited disease and w as the single most sensitive method (75%) in the others, Limited pancr eatic disease could not be identified preoperatively, and the present means of biochemical pancreatic tumor identification invariably involv ed the presence of at least one lesion greater than or equal to 7 mm i n diameter, Conventional pancreatic imaging is insensitive and nonspec ific for recognizing even substantial pancreatic tumors :associated wi th MEN-I.