Feasibility of EUS-FNA for gastric submucosal lesion using a prototype forward-viewing and curved linear-arrayed echoendoscope with or without new developed attaching cap device; a pilot study

Background and Aim: Since the gastrointestinal stromal tumor (GIST) has malignant potential, it is desirable to remove it surgically even if it is a small GIST. Therefore, positive diagnosis utilizing EUS-FNA is demanded for making a therapeutic strategy of gastrointestinal submucosal lesions (GI-SML). However, it is occasionally difficult to make a diagnosis for small lesion by EUS-FNA using conventional oblique-viewing and curved linear-arrayed echoendoscope (OV-ES). Recently, forward-viewing and curved linear-arrayed echoendoscope (FV-ES) was developed. It is possible that this scope is easy to convey power to an object at needling, in addition, can attach cap device on the tip to fix an object. Therefore, we thought that EUS-FNA using FV-ES for SML might be easily performed in comparison with OV-ES. Until now, there is no assessment of EUS-FNA using FV-ES for GI-SML. To evaluate whether FV-ES is satisfactorily available to perform EUS-FNA for GI-SML, we assessed the operativity and feasibility of this new equipment.

Patients and Methods:

A total number of 7 patients who had gastrointestinal SML (1 in esophageal, 5 in gastric, and 1 in duodenal) were enrolled in this pilot study. EUS-FNA was performed using FV-ES and 22-gauge needle. Rapid on-site pathology was done during EUS-FNA in all cases. The primary end point was success rate of obtaining adequate specimen for histological examination for immunostaining, complication, and technical impression of operator.

Results:

Mean size was 28.6mm (range 12–50mm) in diameter, and location in the stomach was 1 in cardia and 4 in body. EUS-FNA was performed in all organs, even esophagus. Mean number of needling was 4.8 (range 4–7), and the success rate of obtaining adequate specimen was 85.7% (6/7). Attached cap devise was used in 3 patients, the cap achieved a function to fix the SML well during EUS-FNA. No complication was seen. Interview to operator revealed an advantage of FV-ES compared with OV-ES; needling power was easy to come to an object without missing it. In addition, although FV-ES has a narrower scanning range (90 degree) in comparison with OV-ES (180 degree), there were no difficulties during EUS-FNA.

Conclusion:

In spite of small study, presented pilot study demonstrated the feasibility with safe of EUS-FNA for GI-SML using a prototype FV-ES. Especially, the attached cap device would be useful.