Serous cystic tumors (SCTs) of the pancreas are benign lesions often incidentally diagnosed (1,2). Their association with chronic obstructive pancreatitis (COP) has not been investigated so far, and it is unclear whether this aspect may be relevant for their management. In the present study we evaluated the prevalence of COP in patients resected for SCTs and its association with tumor size, postoperative complications and long-term pancreatic exocrine/endocrine function. Specimens of pancreatic resection margins from 65 consecutive patients were analyzed by an experienced pathologist. COP was classified in 4 stages (focal, mild, moderate and severe) according to the degree of fibrosis, atrophy and main pancreatic duct diameter. Clinical data were retrieved from our electronic database. Furthermore, quality of life (EORTC QLQC30), exocrine and endocrine pancreatic function were evaluated.COP was found in 11 out of 65 (17%) patients resected for SCTs and classified as focal in 2 cases (18.2%), mild in 2 (18.2%), moderate in 3 (22.3%) and severe in 4 cases (36.3%). It was mainly associated with lesions located in the head (8 [72.7%] vs 3 lesions [27.3%] in the body/tail). Median age was significantly higher in patients with COP (59 yrs vs 49 years, p=0.05). Also, tumor size was significantly greater in COP group (median diameter 5.1 cm vs 3.7 cm, p=0.026). No significant difference in main pancreatic duct diameter was found. There were no postoperative deaths. The rate of postoperative complications, and in particular of pancreatic fistula, was not significantly different in the two groups. Median follow-up was 55 months (range 14-187). There were no differences in terms of quality of life. However, the rate of both exocrine and endocrine insufficiency was significantly higher in patients with COP (steatorrhea 20% versus 11.1%, p=0.05; postoperative diabetes 10% versus 4.6%, p=0.02).SCTs of the pancreas are frequently associated with COP, especially when maximum tumor diameter is > 5cm. Once signs of COP have developed, long-term impairment of exocrine and endocrine functions following pancreatic surgery is significantly higher. Accordingly, direct/indirect evidence of COP at presentation or during follow-up may represent an additional parameter for recommending surgical resection. References: 1.Tseng JF, Warshaw AL, Sahani DV, et al. Serous cystadenoma of the pancreas: tumor growth rates and recommendations for treatment. Ann Surg 2005; 242:413-419.2.Bassi C, Salvia R, Molinari E, et al. Management of 100 consecutive cases of pancreatic serous cystadenoma: wait for symptoms and see at imaging or vice versa? World J Surg 2003; 27:319-323.