Background: Synchronous cystic lesions of the pancreas with different pathophysiology in the same patient are a rare occurrence.. Case Presentation: We report the incidental finding of a multicystic lesion within the pancreatic head in a morbidly obese woman during workup for bariatric surgery. The lesion contained an intraductal papillary mucinous neoplasm (IPMN) with high-grade dysplasia within an acinar cell cystadenoma (ACA). ACAs are rare tumors first described in 2002. Conclusion: To date, there have been no published reports of synchronous IPMN within an ACA. This case report intends to increase provider awareness of these lesions as well as highlight the importance of surveillance and careful histological examination of heterogeneous cystic lesions of the pancreas.