A comparative study of endoscopic ultrasound guided fine needle aspiration with and without a stylet

Abstract

Background: Despite lack of evidence, use of a stylet during endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) is assumed to improve the quality and diagnostic yield of specimens.

Aim: The purpose of this study was to compare EUS-FNA specimens obtained with stylet (S+) and without stylet (S-) for: (i) cellularity, contamination, adequacy, and amount of blood and (ii) diagnostic yield of malignancy.

Methods: Patients who underwent EUS-FNA of solid lesions by two experienced endosonographers at a tertiary referral center using a 22-gauge FNA needle with suction were included. Stylet was used for all EUS-FNA procedures performed between January 2006 and September 2007 and no stylet was used between October 2007 and April 2009 allowing comparison between the two techniques. Cytology slides were retrieved, de-identified and evaluated by two experienced cytopathologists blinded to FNA technique. Slides were evaluated for cellularity, degree of contamination, adequacy, amount of blood and cytologic diagnosis. Fisher's exact and unpaired t-test were used for comparative analysis.

Results: A total of 162 patients with 228 lesions were included. FNA of 106 and 122 lesions each was performed in the S+ and S- groups, respectively. FNA sites included pancreas [41 (18%)], lymph node [125 (55%)], liver [20 (9%)], adrenal [21 (9%)] and others [21 (9%)]. No significant differences in the cellularity (P=0.37), contamination (P=0.18), significant blood (P=0.42) and adequacy of specimen (P=0.45) were found between S+ and S- specimens. There was no statistically significant difference in the diagnostic yield of malignant lesions (P=0.48).

Conclusions: The use of stylet during FNA does not appear to confer any advantage with regards to the adequacy of specimen or diagnostic yield of malignancy.