Endoscopic ultrasound guided fine-needle aspiration cytology of pancreatic carcinoma: a 3-year experience and review of the literature.

Background: Endoscopic ultrasound-guided fine-needle aspiration biopsy (EUS-FNAB) of small pancreatic lesions that are undetectable by computed tomography has gained wide acceptance for the procurement of cells for diagnostic purposes. However, this technique is not without difficulty. The authors examined the sensitivity, specificity, and positive and negative predictive values (PPV and NPV, respectively) of this technique in the evaluation of patients with pancreatic biliary duct strictures/masses. The authors were interested in reviewing their cases of pancreatic adenocarcinoma of ductal type and finding the sources of their false-negative cases.

Methods: A computer search was performed between January 1998 and July 2001. For the last 3 years, a total of 80 cases of suspected ductal adenocarcinoma of the pancreas was identified. Thirty-four patients (42%) underwent a subsequent Whipple procedure or biopsy. Cytologic and histologic correlation was performed in these cases. The rest of the 23 patients (29%) considered to be positive and the 23 patients (29%) considered to be negative underwent no subsequent biopsy and were followed clinically. Cases termed "suspicious" on cytology were considered positive and those termed "atypical cytology" were considered negative in the authors' final calculation. The causes of the false-negative diagnoses were evaluated carefully.

Results: Of the 34 cases followed with subsequent tissue biopsy or surgery; 12 were confirmed to be positive, 12 were confirmed to be negative, and 10 were considered to be false-negative. Previously identified cytomorphologic features of malignancy were used to review all cases. These features were: loss of the honeycomb pattern (100%), anisonucleosis (100%), nuclear contour irregularity (100%), a high nuclear/cytoplasmic ratio (100%), paranuclear chromatin clearing (77%), and the presence of prominent nucleoli in the absence of inflammatory cells (77%). The causes of the 10 false-negative cases were technical difficulty of procuring material in 6 cases, the nature of the lesion in 2 cases, and the scarcity of lesional tissue in 2 cases.

Conclusions: Using strict cytoarchitectural and cytomorphologic criteria of malignancy for ductal pancreatic lesions previously described in the literature, the sensitivity of this technique at the study institution was 78% with a specificity of 100%. The PPV and NPV of this technique were 100% and 78%, respectively. The most common causes of the false-negative results in descending order were the technical aspect of the procedure, the size and nature of the lesion, and the scarcity of lesional tissue.