Pancreatic Serous Cystadenoma: A Continuing Diagnostic Challenge.

Objective: To understand the natural history of serous cystadenoma (SCA), and the diagnostic accuracy of SCA and identify possible factors that lead to the correct diagnosis.

Background: SCA is a benign cystic pancreatic neoplasm of the pancreas, accounting for ~15% of resected pancreatic cysts. Current recommendations are to proceed with surgical resection in symptomatic patients or when there is uncertainty regarding diagnosis. The latter continues to be a challenge since intentional resection of an SCA accounts for only a minority of resected cases.

Methods: Retrospective single-institution review of patients who on final pathology had a diagnosis of pancreatic SCA and of patients who had this diagnosis and were managed nonoperatively. Demographic data, cyst characteristics, and growth rate were collected for analysis.

Results: A total of 250 patients were analyzed. Median age was 62 (range: 22-89), 65% were females, and 34% had symptoms. Tumor size ranged from 0.6 to 20, with a median of 3.4 cm. The morphologic appearance was microcystic in 58%, macrocystic in 16%, mixed-type in 23%, and solid in 3%. Pancreatic duct dilation and pancreatic atrophy were found in 22% and 14%, respectively. The average growth rate was 1.8 mm/year regardless of tumor size. Of the 172 patients who underwent surgery, SCA was the preoperative diagnosis in only 33%. A correct diagnosis was independently associated with large tumors and cyst fluid carcinoembryonic antigen analysis. Pancreatic duct dilation was independently associated with an in-growing cyst and the presence of calcification.

Conclusions: SCA is a slow-growing pancreatic cystic neoplasm that is mostly asymptomatic but can lead to pancreatic duct dilation and atrophy in some patients. A surprisingly small number of correct preoperative diagnoses confirms that this entity continues to be a diagnostic challenge. A more thorough preoperative workup that includes endoscopic ultrasonography should improve the rate of misdiagnosis.