Sa1193 Quantitative Endoscopic Ultrasound Elastography (Q-EUS-E) in the Differential Diagnosis of Solid Pancreatic Masses: A Validation Study

Abstract

Endoscopic ultrasound (EUS) guided biopsy allows cytologic and/or histologic diagnosis of sub-mucosal lesions of the gastrointestinal tract (GIT). The diagnostic yield with fine needle aspiration (FNA), however, is often unsatisfactory (~30-40%). A newly developed Pro-Core needle (PCN) is able to obtain core tissue and may improve diagnostic yield. AIM: To compare the performance of two EUS guided biopsy needle systems, FNA versus PCN, in the evaluation of sub-mucosal lesions in the upper GIT. METHODS: Data related to patients referred for EUS and possible guided biopsy of sub-mucosal lesions in the upper GIT over 24 months were retrospectively reviewed. All specimens were prepared as cell-block for histo-cytological analysis. Measured outcomes were presence of diagnostic material, ability to perform immunohistochemistry (IHC), provision of a diagnosis, and complication. RESULTS: Of 84 patients who had EUS evaluation of an upper GIT sub-mucosal lesion, 30 patients did not have biopsy (lipoma=14, duplication cysts=6, vascular compression=1 and no abnormality=9). EUS-guided biopsy were performed in 54 patients, using 19-22G FNA (n=34) and 22G PCN (n=20) system, to clarify the tissue diagnosis of a hypo-echoic submucosal mass. There were no differences in age (61.1±2.6 vs. 59.2±5.3 yrs), gender (13M:17F vs. 3M:8F), site (22gastric : 8duodenal : 4esophageal vs. 17gastric : 1duodenal : 2esophageal) or size (2.1±0.1 vs. 2.1±0.3 cm) of biopsied lesion between the FNA and PCN groups, respectively. Biopsy with PCN obtained significantly more diagnostic material than FNA, leading to a substantially higher diagnostic yield (18/20 vs. 14/34; P ,0.001). Of the 17 suspected spindle cell tumours from the PCN group, IHC study (c-kit stain) were successful in all cases and provided tissue confirmation of 10 leiomyomas and 7 gastrointestinal stromal tumours (GIST). In contrast, only 7/14 patients with FNA needle had sufficient material for additional IHC study (P=0.008, vs. PCN), confirming GIST in only 3/12 of suspected spindle cell tumours. Neither group had abdominal pain or clinical significant bleeding after the biopsy. CONCLUSIONS: EUS guided biopsy with 22G PCN has substantially higher histocytological yield than that with FNA needles (90% vs. 41%) and without any complication. PCN, therefore, should be the needle of choice for tissue acquisition of sub-mucosal lesions in the GIT.