Endometriosis-associated Tumor of the Sigmoid Colon—A Case Report—

Abstract

The patient was a 75-year-old woman. She had a history of a total hysterectomy and light oophorectomy for light endometriotic cysts at the age of 45 years. She went to her previous doctor because she had a positive fecal occult blood test. Colonoscopy showed a type 3 tumor at the sigmoid colon. The pathological diagnosis was adenocarcinoma. She was referred to our hospital for surgery, and computed tomography showed no distant metastasis. She was diagnosed with sigmoid colon cancer. The preoperative stage was considered cT3N1bM0, cStage III b. Laparoscopic sigmoidectomy with D3 lymph node dissection was performed, and she was discharged on the 10th postoperative day. On pathological examination, the tumor was located mainly in the muscularis propria of the sigmoid colon and was positive for estrogen receptors on immunohistochemistry. Endometrial glands and stroma were present adjacent to the tumor. She was diagnosed with endometrioid carcinoma arising from endometriosis of the sigmoid colon. This was considered to be an endometriosis-associated intestinal tumor (EAIT). Since malignant transformation from intestinal endometriosis is rare, this case is presented along with a review of relevant literature.