Clinicopathologic characteristics of patients with resected multifocal intraductal papillary mucinous neoplasm of the pancreas

Background: Intraductal papillary mucinous neoplasms of the pancreas are defined as mucin-producing neoplasms arising in the main pancreatic duct (main duct type), its major branches (branch duct type), or in both (mixed type). Intraductal papillary mucinous neoplasms of the pancreas can occur as a single collection of cysts or as multifocal lesions. While subtypes of intraductal papillary mucinous neoplasms of the pancreas are well described in literature, little is known about the importance of multifocal intraductal papillary mucinous neoplasms of the pancreas. This study evaluated the clinicopathologic characteristics of patients with surgically resected, multifocal intraductal papillary mucinous neoplasm of the pancreas.

Methods: Clinicopathologic features and preoperative imaging of patients resected for multifocal intraductal papillary mucinous neoplasm of the pancreas defined as intraductal papillary mucinous neoplasm of the pancreas occurring in more than just 1 area, from January 2004 to July 2010 at the Department of Surgery, University of Heidelberg were analyzed. Preoperative parameters, including number of cysts, cyst size, presence of nodules, and epidemiologic data, were assessed and compared to patients with unifocal intraductal papillary mucinous neoplasms of the pancreas.

Results: Among 287 patients with resected intraductal papillary mucinous neoplasms of the pancreas, 51 patients (17.8%) with multifocal cystic pancreatic lesions were identified by preoperative imaging. The median age of patients with multifocal intraductal papillary mucinous neoplasms of the pancreas was ≥ 68 years (P = .002) compared to patients with unifocal intraductal papillary mucinous neoplasm of the pancreas (median age, 64 years). Thirty-one multifocal intraductal papillary mucinous neoplasms of the pancreas were of mixed type (60.8%), 15 of branch duct type (29.4%), and 5 of main duct type (9.8%). Histologically, 10 multifocal intraductal papillary mucinous neoplasms of the pancreas had low-grade dysplasia (19.6%), 11 had moderate dysplasia (21.6%), 6 had high-grade dysplasia (11.8%), and 24 had invasive carcinoma (47.1%).

Conclusion: Most multifocal intraductal papillary mucinous neoplasms of the pancreas involve the main pancreatic duct and synchronously its major side branches (mixed type). Patients with multifocal intraductal papillary mucinous neoplasm of the pancreas present at an older age compared to patients with single cystic pancreatic neoplasm. The risk of harboring malignancy-nearly 60% in the present study-seems to be increased in patients with multifocal intraductal papillary mucinous neoplasms of the pancreas compared to single lesions.