A 46-year-old, female patient was admitted to our hospital after testing positive on a fecal occult blood test. Colonoscopy revealed a submucosal tumor in the lower rectum with poor extension. Computed tomography and magnetic resonance imaging revealed a 23-mm, extramural mass with homogeneous enhancement. Endoscopic ultrasound showed an heterogeneous, hypo-echoic, extramural growth, mainly in the fourth layer of the intestinal mucosa. For definitive diagnosis, a mucosal cutting biopsy was performed using a disposable endo-knife. Pathological analysis of the biopsy specimen revealed endometrial cells that were positive for estrogen receptors. Based on this finding, intestinal endometriosis was diagnosed.
Mucosal cutting biopsy can be used in conjunction with EUS to obtain a sufficient amount of tissue safely and is a useful diagnostic method for submucosal tumors such as in the present case.
