Feasibility and Yield of a New 20 G ProCore Needle With Coiled Sheath in the Gastrointestinal Subepithelial Tumors

The exact incidence of subepithelial tumors (SETs) in the gastrointestinal (GI) tract is unknown, but the prevalence of gastric SETs detected during routine esophagogastroduodenoscopy is 0.36%. GI SETs may include leiomyoma, GI stromal tumor (GIST), schwannoma, lipoma, cyst, or ectopic pancreas. Surgical resection is the principal diagnostic and therapeutic method for SETs, especially for large and symptomatic ones. Preoperative pathological diagnosis of SETs may facilitate clinical decision making, but conventional endoscopic forceps biopsy does not yield adequate amounts of subepithelial tissue for definitive diagnosis.

Although endoscopic ultrasonography (EUS) is the best imaging modality for the evaluation of SETs, it cannot substitute histopathological diagnosis. EUS-guided fine-needle aspiration (EUS-FNA) may provide adequate amounts of tissue for the diagnosis of SETs, but it does not always afford adequate samples for immunohistochemical analysis because of the often small number of cells obtained by aspiration. Since some SETs, especially GI mesenchymal tumors such as GIST or schwannoma, have varied morphologic appearances, and diagnosis using a small biopsy is not straightforward, immunohistochemical analysis is strongly advisable, if not essential. EUS-guided Trucut biopsy (EUS-TNB) may overcome the limitations of EUS-FNA in procuring sufficient core tissue specimens. Although EUS-TNB is more accurate than EUS-FNA for diagnosing GI mesenchymal tumors, the rigidity of its 19-gauge (G) caliber and the mechanical friction of the firing mechanism produced by the torqued echoendoscope limit its use for SETs located in the gastric antrum and duodenum. Therefore, a needle facilitating adequate histological core sampling with easy maneuverability needs to be established. A 19G EUS-guided fine-needle biopsy (EUS-FNB) device with ProCore reverse-bevel technology was recently introduced. A multicenter study revealed that histological samples could be successfully obtained using this needle in most patients having GI SETs, with a diagnostic accuracy of >80%.10 However, because of technical difficulties with this needle in the gastric antrum and duodenum, the same FNB device was recently developed in a 20 G platform with coiled sheath. This prospective, multicenter study aimed to evaluate feasibility, yield, and diagnostic accuracy of a newly developed 20 G ProCore needle with coiled sheath in patients with GI SETs.