Intraductal Papillary Mucinous Tumors of the Pancreas Comprise 2 Clinical Subtypes: Differences in Clinical Characteristics and Surgical Management

Abstract

HYPOTHESIS: Intraductal papillary mucinous tumors (IPMTs) of the pancreas may be meaningfully construed as representing 2 clinically distinct subtypes: main duct tumors (MDT) and branch duct tumors (BDT). DESIGN: Retrospective study. SETTING: University hospital from January 1988 through December 1994. PATIENTS AND INTERVENTION: We reviewed diagnostic findings and late results of surgical treatment in 30 patients with IPMT. RESULTS: The tumor was located in the head of the pancreas more often in BDT than in MDT (65% [11/17] and 23% [3/13], respectively). Of the 13 patients with MDTs, 12 (92%) had intraductal papillary adenocarcinoma (noninvasive and minimally invasive types) and/or carcinoma in situ (carcinoma in situ: low papillary and/or flat tumor cells), and 3 (23%) had stromal invasion. Of the 17 patients with BDTs, 5 (29%) had intraductal papillary adenocarcinoma and/or carcinoma in situ. Two pancreatoduodenectomies and 8 pylorus-preserving pancreatoduodenectomies were performed in 10 of the 17 patients with BDTs, distal pancreatectomy in 7 patients with MDTs, and total pancreatectomy in 4 patients with MDTs. The 5-year survival rates were 47% for MDT and 90% for BDT. Four of 6 patients with MDTs who died had local recurrence. One patient died of liver metastasis and 1 of esophageal cancer. Only 1 patient with BDT of the 2 who died had recurrent disease. CONCLUSIONS: Intraductal papillary mucinous tumors may be composed of 2 clinically distinct subtypes: MDTs and BDTs. Initially, although distal pancreatectomy can be recommended for most MDTs, the need for cancer-free margins in this more aggressive type may necessitate total pancreatectomy. Pylorus-perserving pancreatoduodenectomies is recommended for most BDTs, but, because these tumors are more often adenomas, a good prognosis can be expected.