Efficacy of Mucosal Cutting Biopsy for the Histopathological Diagnosis of Gastric Submucosal Tumors

Background: Gastrointestinal stromal tumors occur frequently. Endoscopic ultrasound-guided fine needle aspiration (EUS-FNA) is performed commonly for diagnosis. However, the success rate of histological diagnosis is insufficient when the submucosal tumor (SMT) is small. Recently, another technique, mucosal cutting biopsy (MCB) has been reported. The aim of this study is to evaluate the efficacy and safety of MCB. Method: Between January 2012 and August 2018, MCB and EUS-FNA were performed 16 and 31 times for diagnosing gastric SMT. The diagnostic rate, the rate of successful immunohistochemistry, and the safety were reviewed. Difficult locations for EUS-FNA were also evaluated. Results: The mean SMT sizes measured on MCB and EUS-FNA were 21.2 and 36.2 mm. The diagnostic rates of MCB and EUS-FNA were almost the same (88 vs. 81%), but successful immunohistochemistry was significantly higher in the MCB group (93 vs. 59%, p = 0.03). In the subgroup of SMTs < 20 mm, the successful histological diagnosis rate from EUS-FNA was relatively low. There were no complications. Failures of EUS-FNA were more frequent in the middle third of the stomach. Conclusions: MCB was an effective procedure for diagnosing gastric SMT, especially in the case of small SMTs located at the middle third of the stomach.