Diagnostic accuracy of endoscopic ultrasound-guided fine needle aspiration cytology of pancreatic lesions

Abstract

Background: Endoscopic ultrasound-guided fine needle aspiration cytology (EUS-FNAC) is currently the most commonly used procedure for obtaining cytologic specimens of the pancreas. It is accurate, minimally invasive, safe and cost-effective. However, there is discrepancy between cytological and surgical diagnoses. This study was aimed at evaluating the diagnostic accuracy of EUS-FNAC of the pancreas.

Methods: We performed a retrospective review of 191 cases of pancreatic lesions initially diagnosed by EUS-FNAC with subsequent histological diagnosis between 2010 and 2012 in the Department of Pathology, Seoul National University Hospital. Cytologic and surgical diagnoses were categorized into five groups: negative, benign, atypical, malignant, and insufficient for diagnosis. Subsequently, 167 cases with satisfactory yield in both surgical and cytology specimens were statistically analyzed to determine correlations with diagnosis.

Results: In comparison to surgical diagnoses, cytologic diagnoses were true-positive in 103 cases (61.7%), true-negative in 28 cases (16.8%), false-positive in 9 cases (5.4%), and false-negative in 27 cases (16.1%). The diagnostic accuracy was 78.4%, sensitivity was 79.2%, and specificity was 75.7%. The positive predictive value was 92.0%, and negative predictive value was 50.9%.

Conclusions: EUS-FNAC has high accuracy, sensitivity, specificity and positive predictive value. Overcoming the limitations of EUS-FNAC will make it a useful and reliable diagnostic tool for accurate evaluation of pancreatic lesions.

Keywords: Accuracy; Diagnosis; Endoscopic ultrasound-guided fine needle aspiration cytology; Pancreas.

Fig. 1.

Cytologic specimens with false-negative discrepant results (Table 4). (A) Case No. 31 with histological diagnosis of ductal adenocarinoma. Obvious malignant cell clusters that resemble adenocarcinoma. (B, C) Case No. 32 with histological diagnosis of ductal adenocarinoma. Malignant cell clusters are intermixed with and camouflaged by a massive amount of benign parenchymal cells. (D) Case No. 35 with histological diagnosis of intraductal papillary mucinous neoplasm. Some mucin-producing epithelial cells with suspicious atypism are observed.

Fig. 2.

Cytologic specimen with corresponding histological diagnosis of schwannoma. Cytopathologic features present mostly in tissue fragments or in fascicles, with cells fusiform and elongated with poorly defined cell borders, a low nuclear-cytoplasmic ratio with long and wavy nuclei, inconspicuous nucleoli and pale cytoplasm.