Intraductal papillary or mucinous tumors (IPMT) of the pancreas: report of a case series and review of the literature

Abstract

Objective: Despite a better understanding of these conditions, intraductal papillary or mucinous tumors (IPMT) of the pancreas still present difficulty relating to the predictive factors of malignancy and the risk of relapse after surgical resection. The aim of this study was to report on our experience and to compare it to previously published cases.

Methods: We studied retrospectively 26 patients (mean age 60.3 yr) presenting with IPMT. Of the 26 patients, 19 had surgical resection and seven did not. The main clinical feature was acute pancreatitis occurring in 38% of the patients. Segmental pancreatectomy was performed in all the cases. At pathological assessment of resection margins, tumor resection was considered as complete in 17 cases. Margins exhibited benign mucinous involvement, and resection was considered to be incomplete in one multifocal case and in one case with diffuse spread of the tumor.

Results: A total of 11 tumors were benign and five were malignant. Carcinomas were invasive in four cases (two invading the pancreatic parenchyma, one the duodenum, and one the peripancreatic nodes) and in situ in one case. Malignancy was not diagnosed preoperatively except when invasion was evident (duodenal spread). Although main pancreatic duct type and obstructive jaundice appeared as suggestive features for the risk of malignancy, no reliable preoperative predictive factors for malignancy could be identified as regarding to clinical parameters, biological examinations, carcinoembryonic antigen or CA19-9 levels in serum or in pure pancreatic juice, imaging, and cytological methods. Within 40.8 months mean follow-up after surgery (range 2-96 months), three patients (16%), two with malignant and one with benign tumor, had tumor relapse after respectively 7, 27, and 14 months. Margins were positive without malignant features in the two malignant cases and negative in the other case. Tumor relapse was malignant with diffuse spreading in the three cases, and the patients died within 34 months after surgical resection.

Conclusions: Our series and the review of the literature indicate that preoperative indicators of malignancy in IPMT are still lacking. Concerning resection margins, complete tumor resection is usually possible by segmental pancreatectomy. Malignant relapses are not exceptional. Incomplete resection and diffuse or multifocal tumor represent poor prognostic factors. Total pancreatectomy should be considered in such cases.