Unusual case of adenocarcinoma arising in endometriosis mimicking colorectalcancer in a young woman with a Mullerian anomaly

Objective: To report a case of endometrioid adenocarcinoma that arose in endometriosis mimicking colorectal cancer in a young woman with a Mullerian anomaly. Design: A case report. Setting: A university hospital. Patient(s): A 31-year-old, white nulligravida woman with a history of two previous laparoscopies for infertility and chronic pelvic pain. A solid rectosigmoid mass adherent to the left pelvic sidewall was found in this patient. Intervention(s): The patient was subjected to an exploratory laparotomy followed by adjuvant chemotherapy. Main Outcome Measure(s): Surgical findings and histopathological observations are included in this report. Result(s): Intraoperative and histologic examinations revealed endometriosis-associated colorectal cancer. Conclusion(s): Although a rare event, this condition should be considered in the diagnosis of women with a previous history of pelvic endometriosis, Mullerian malformation, abdominal pain, constipation, or rectal bleeding.