Influence of on-site cytopathology evaluation on the diagnostic accuracy of endoscopic ultrasound-guided fine needle aspiration (EUS-FNA) of solid pancreatic masses.

Objectives: The aim of this study was to evaluate the influence of on-site cytopathological evaluation on the diagnostic yield of endoscopic ultrasound (EUS)-guided fine needle aspiration (FNA) for the differential diagnosis of solid pancreatic masses in an unselected series of consecutive patients.
Methods: Patients undergoing EUS-guided FNA of solid pancreatic lesions over a 2-year study period were included. Samples were either evaluated on site by a cytopathologist or processed by the endoscopist and sent to the pathology department for evaluation. Diagnostic accuracy for malignancy, number of needle passes, adequate-specimen collection rate, cytological diagnosis, and final diagnosis, and complication rate according to the presence or absence of on-site cytopathologist were evaluated.
Results: A total of 182 patients were included. An on-site cytopathologist was available in 95 cases (52.2%). There was no difference between groups in terms of age, sex, location, and size of the lesions. A significantly higher number of needle passes was performed when an on-site cytopathologist was not available (3.5±1.0 vs. 2.0±0.7; P<0.001). The presence of an on-site cytopathologist was associated with a significantly lower number of inadequate samples (1.0 vs. 12.6%, P=0.002), and a significantly higher diagnostic sensitivity (96.2 vs. 78.2%; P=0.002) and overall accuracy (96.8 vs. 86.2%; P=0.013) for malignancy. Three patients developed complications (two acute pancreatitis, one local bleeding), all of them belonging to the group without on-site cytopathology.
Conclusions: On-site cytopathological evaluation improves the diagnostic yield of EUS-guided FNA for the cytological diagnosis of solid pancreatic masses. This is associated with a significantly lower number of inadequate samples and a lower number of needle passes.