Mucosal cutting biopsy technique for histological diagnosis of suspected gastrointestinal stromal tumors of the stomach

Background and Aim The Japanese Gastrointestinal Stromal Tumor (GIST) therapeutic guidelines recommend endoscopic ultrasound-guided fine-needle aspiration biopsy for histological diagnosis. However, before 2010, this technique was only carried out at a minority of medical institutions in Japan. In the present study, we investigated the usefulness of mucosal cutting biopsy. Methods In 18 asymptomatic gastric submucosal tumors, mucosal cutting biopsies were carried out. We examined tumor size, tumor site (lower third: L; middle third: M; upper third: U), histopathological diagnostic yield and complications. In cases that proceeded to surgical resection with a diagnosis of GIST, we compared the pre- and postoperative histopathological diagnosis, and the histological degrees of malignancy. Results The tumors had a mean size of 20.3mm and were located at the L site in five cases, M in four, and U in nine. Histological diagnosis of submucosal tumor was obtained in all the cases. (GIST, n=13; heterotopic pancreas, n=2; and leiomyoma, n=3). No complications (e.g. bleeding, perforation or peritonitis) were seen after this procedure. In all 11 patients with GIST who underwent surgical resection, the histopathological findings from the mucosal cutting biopsy specimens were similar to those from the surgically resected specimens, with agreement between the immunostaining findings and the histological degree of malignancy (90.9%) in 10 patients. Conclusions The mucosal cutting biopsy technique is a useful diagnostic modality for the diagnosis of gastric GIST and for selection of the appropriate treatment.