A case report: Rectal endometriosis mimicking rectal cancer

Introduction: Rectal endometriosis is rare in women and imaging characteristics are similar with that of rectal cancer, which is one of the most common malignancies. Presentation of case: A 36 years old woman with a suspicious diagnosis of cervical carcinoma in a tertiary hospital visited our hospital, complaining about vaginal bleeding after copulation for six months, accompanying with constipation and diameter-thinning stool. Vaginal and cervical biopsy only showed chronic inflammation. Colonoscopy found a mass at the rectum 4 cm from the anus, but the biopsy showed different diagnoses. Partial resection was eventually operated and the final diagnosis was confirmed as rectal endometriosis. Discussion: Rectal endometriosis is prone to be misdiagnosed as rectal cancer. Small specimen is sometimes insufficient to make a correct diagnosis. Extensive examination should be done to confirm the diagnosis and rash decision should never be encouraging. Conclusion: Rectal endometriosis should always be considered as one of the differential diagnoses in female who have a mass at the rectum. An adequate specimen should be obtained to confirm the histopathological diagnosis.