Introduction: Recent international consensus guidelines propose that all cystic pancreatic tumors less than 3 cm in asymptomatic patients with no radiographic features concerning for malignancy are safe to observe, however there is little published data to support this recommendation. The purpose of this study was to determine the incidence of malignancy in this group of patients using pancreatic resection databases from 4 high volume pancreatic centers to assess the appropriateness of these guidelines.
Methods: All pancreatic resections performed for cystic neoplasms < 3 cm in size were evaluated over the time period of 1998-2006. One hundred fifty eight cases were identified and the clinical, radiographic, and pathological data was reviewed. Factors analyzed as potential predictors of malignancy included age, gender, and symptoms (abdominal pain, nausea and vomiting, jaundice, presence of pancreatitis, unexplained weight loss, anorexia) and radiographic features suggestive of malignancy by either CT , MRI, or EUS (presence of solid component, lymphadenopathy, or dilated main pancreatic duct or common bile duct).
Results: Among the 158 pancreatic resections for cystic pancreatic tumors < 3 cm, 130 cases were benign (37 serous cystadenomas, 33 mucinous cystic neoplasms, 58 intraductal papillary mucinous neoplasms (IPMN), 1 cystic papillary tumor, 1 cystic islet cell tumor), while 28 cases were malignant (14 mucinous cystic adenocarcinomas and 14 invasive carcinomas arising in the setting of IPMN). A greater incidence of cystic neoplasms was seen in females (94/158, 59%). Gender was a predictor of malignant pathology, with males having a higher incidence of malignancy (17/64, 27%) compared to females (11/94, 12%) (p<0.02). Older age was also associated with malignancy (mean age 66.7 yrs. in patients with malignant disease vs. 62.7 yrs. in patients with benign lesions (p<0.01). A great majority of the patients with malignancy were symptomatic (27/28, 96%), with abdominal pain being the most common symptom (57%), followed by weight loss (35%), jaundice (32%), and pancreatitis (14%). 24/28 (86%) patients with malignant lesions had at least 1 radiographic features concerning for malignancy. All of the 28 patients with malignancy were either symptomatic or had concerning radiographic features for malignancy.
Conclusions: As all patients with malignancy had either symptoms or concerning imaging, this multi-institutional report supports the guidelines proposed by the International Consensus Conference. We conclude that the risk of malignancy in asymptomatic patients with pancreatic cystic tumors < 3cm with no worrisome radiographic features is negligible.