Abstract
Gastrointestinal stromal tumors (GISTs) are diagnosed by histopathological examination with immunostaining. While histopathological assessment using endoscopic ultrasound-guided fine needle aspiration biopsy (EUS-FNAB) is recommended in the GIST guidelines, the accuracy of diagnosis of small gastric submucosal tumors of less than 2cm remains to be improved. Direct-observation biopsy by mucosal cutting for gastric submucosal tumors allows us to directly expose small tumors of less than 2cm, and thus, a sufficient amount of tumor tissue can be obtained for histopathological diagnosis. In the present study, we evaluated the results of direct-observation biopsy by mucosal cutting in 6 patients with a gastric submucosal tumor at our institute. Among the 6 biopsied patients, 3 patients were diagnosed as having GISTs, of which the mean tumor size was 13.4mm. Immunostaining was carried out in all 3 patients and the Ki-67 labeling index of the biopsy specimens was the same as that in the specimens obtained from surgery. Our results suggest that direct-observation biopsy by mucosal cutting is useful for diagnosing gastric submucosal tumors of less than 2cm, for which EUS-FNAB sometimes fails to provide an accurate diagnosis.
