Role of repeated endoscopic ultrasound-guided fine needle aspiration in small solid pancreatic masses with previous indeterminate and negative cytological findings.

INTRODUCTION: Despite advances in imaging techniques, the differentiation between pancreatic cancer and benign lesions remains difficult. Endoscopic ultrasound-guided fine needle aspiration (EUS-FNA) is an effective method for providing tissue diagnosis, but problems occur when lesions are small or the cytological diagnosis is indeterminate.

AIM: To prospectively evaluate the utility of EUS-FNA in patients with small solid pancreatic lesions and those with initial indeterminate or negative cytological diagnosis.

METHODS: During the study period we performed a total of 119 EUS-FNA procedures on 46 patients (mean age 56.3 years) for 47 small solid pancreatic lesions (range 7-30 mm, mean 17.2 mm in diameter). FNAs were performed in the presence of a cytopathologist. If cytological diagnoses were indeterminate, EUS-FNA was repeated within 3 weeks. Diagnoses were confirmed histologically or by follow-up (clinical and imaging: EUS +/- FNA and CT).

RESULTS: Localization of the lesions: head 28 (60%), uncinate process 4 (9%), body 11 (23%) and tail 4 (9%). On average, 3.7 passes were performed. We observed no complications. Initial cytological findings were: malignant 17 (36%), benign 21 (45%), and indeterminate 9 (19%). 8 (78%) of the indeterminate findings were confirmed to be malignant on repeated procedures. A diagnosis of pancreatic cancer was subsequently confirmed in 1 patient who had a benign cytological finding. 19 patients underwent surgery. Histology confirmed a neoplasm in all cases. Sensitivity, specificity, positive predictive value, negative predictive value and diagnostic accuracy were 68, 100, 100, 73 and 83%, respectively. After repeated EUS-FNAs of indeterminate findings sensitivity, negative predictive value and diagnostic accuracy rose to 92, 77 and 96%, respectively.

CONCLUSION: EUS-FNA is a highly effective method for providing tissue diagnosis in patients with small solid pancreatic masses. Repeated procedures enhanced diagnostic accuracy in indeterminate findings, among which was high percentage of malignancies. EUS-FNA reduced the number of operations in patients with pancreatic solid masses.