Endosonographic diagnosis of intraductal papillary‐mucinous pancreatic tumors by intraductal ultrasonography

Abstract

Background: Intraductal papillary‐mucinous pancreatic tumors (IPMT) are intraductal lesions formed by mucin‐producing epithelium, which proliferates in a papillary pattern, and presents a spectrum from hyperplasia to adenocarcinoma. The value of intraductal ultrasonography (IDUS) for excluding malignancy has not been assessed in a case series previously.Methods: Intraductal ultrasonography was performed in 17 patients with IPMT (12 with adenocarcinoma and five with adenoma) between November 1993 and June 2002. Intraductal ultrasonography was used to determine the maximum height and maximum cross‐sectional area of protruding lesions. Results were compared after dividing the tumors into three groups: a benign lesion group, a non‐invasive cancer group, and an invasive cancer group. The resection line was located over 10 mm from the edge of the protruding lesion visualized by intraductal ultrasonography.Results: All adenocarcinomas had a height ≥ 5 mm and all benign lesions had a height ≤ 3 mm, with this difference being significant (P = 0.0034). The height of non‐invasive and invasive cancer was similar. The maximum cross‐sectional area of the protrusion was smaller for benign lesions (≤ 15 mm2) than for non‐invasive cancer (≥ 34 mm2, P = 0.0034). The cross‐sectional area of the protrusion was greater in patients with invasive cancer than in those with non‐invasive cancer (P = 0.0367). All surgical margins have remained clear and no patient has suffered from a recurrence during 1 to 8 years of follow‐up computed tomography and ultrasonography.Conclusions: Intraductal ultrasonography can distinguish benign from malignant IPMT based on the height and maximum cross‐sectional area of the protruding tumor.