Objective: Preoperative diagnosis of cystic lesions of the pancreas remains difficult despite improvement in imaging modalities and cystic fluid analysis. The aim of our study was to assess the performance of endoscopic ultrasonography (EUS) and EUS-guided fine needle aspiration (FNA) in the diagnosis of pancreatic cystic lesions.
Methods: Data from a series of 127 consecutive patients with pancreatic cystic lesions were prospectively studied. EUS and EUS-guided FNA were performed in all patients, and cystic material was used for cytological and histological analysis as well as for biochemical and tumor markers analysis. Performance of EUS diagnosis, biochemical and tumor markers, and FNA diagnosis were compared with the final histological diagnosis obtained at surgery or postmortem examination. Sixty-seven patients underwent surgery and therefore constituted our study group.
Results: EUS provided a tentative diagnosis in 113 cases (89%). Cytohistological FNA provided a diagnosis in 98 cases (77%). When the results of EUS and EUS-guided FNA were compared with the final diagnosis (67 cases), EUS correctly identified 49 cases (73%), whereas FNA correctly identified 65 cases (97%). Sensitivity, specificity, positive predictive value, and negative predictive value of EUS and EUS-guided FNA to indicate whether a lesion needed further surgery were 71% and 97%, 30% and 100%, 49% and 100%, and 40% and 95%, respectively. Carbohydrate antigen 19-9 > 50,000 U/ml had a 15% sensitivity and a 81% specificity to distinguish mucinous cysts from other cystic lesions, whereas it had a 86% sensitivity and a 85% specificity to distinguish cystadenocarcinoma from other cystic lesions.
Conclusions: EUS-guided FNA is a valuable tool in the preoperative diagnostic assessment of pancreatic cystic lesions.