The incidence of endometriosis is 8~15% in reproductive age women, of whom 3~37% show intestinal invasion. We
report a case of endometriosis with sigmoid invasion in a 48-year-old female. The patient had bowel habit changes in
accordance with her menstrual cycle, along with lower abdominal pain, tenesmus, and bleeding on defecation. A sigmoid
colon mass was identified on sigmoidoscopic examination. The biopsy results showed typical colonic endometriosis. On
subsequent colonoscopic examinations, the previous lesion showed apparent changes in accordance with menstrual cycle.
Lower anterior resection of the colon and total hysterectomy were successfully performed. We present this case along
with a brief review of the literature.