The natural history of pancreatic lipoma: Does it need observation *

Abstract Background Pancreatic lipomas (PL) are a rare, benign mesenchymal neoplasm. Some patients diagnosed with PL are followed radiographically or referred to a second provider, while others are not followed after incidental diagnosis. In this study we describe 74 cases of intrapancreatic lipomas from a single institution over a 12-year period to elucidate the radiologic and clinical natural history of pancreatic lipoma. Methods In the period from January 2001 to December 2013, we selected patients over the age of 18 diagnosed with PL based on Ultrasound, CT, and MR imaging. Clinical data were coupled with review of the radiographic image. These patients were retrospectively followed to establish the significance of PL. Results PL was identified in 0.012% of all patients undergoing cross-sectional imaging during the studied interval. Lipomas ranged in size at diagnosis from 0.1 cm to 4.8 cm. The majority of patients were asymptomatic at presentation. No patient required intervention or exhibited a change in lipoma diagnosis over a median follow up interval of 41.5 months (range 2–145). 47 patients underwent subsequent imaging with a median of two additional exams (range 2–113) over 31 months (range 1–18). 46/47 (98%) patients with subsequent images showed no discernible growth; 1/47 (2%) had a resolution of the lipoma. Conclusions Pancreatic lipomas are rare benign mesenchymal neoplasms that exhibit stable size and morphology. They are overwhelmingly asymptomatic. The natural history of pancreatic lipoma is benign. Short-term interval observation is prudent to prove stability and help differentiate from early liposarcoma. Extensive follow-up is not likely necessary for this benign lesion.