Synchronous Primary Anorectal Melanoma, Sigmoid Multiple Early Cancers and Descending Adenocarcinoma: A Case Report

Multiple colorectal cancers are extremely rare, few cases can be searched in the literature. Our group only found 6 cases published. We report a case where 3 diseases coexisted summarize the currently available literature. A 75-year-old man presented with changes in his bowel habits and hematochezia. After a colonoscopy with biopsies in a community hospital, he was diagnosed with a descending adenocarcinoma patient. To get further treatment, he came to our hospital. Colonoscopy revealed ulcerative lesions in the descending colon, 2 polypoid lesions in the sigmoid colon, and a protruded lesions in the anorectal. The ulcerative lesions were already diagnosed as adenocarcinoma at the descending colon. So biopsies were taken in the anorectal region, which revealed poorly differentiated melanoma of the anorectal. Computed tomography did not find distant metastases and regional lymphadenopathy. A laparoscopic resection was undertaken to relieve his symptoms and improve the quality of life. The mass showed descending adenocarcinoma, sigmoid multiple early cancers, and poorly differentiated melanoma of the anorectal region. What we can learn is that endoscopy doctors should always be aware of the possibilities of multiple primary cancers for this is important to the treatment and prognosis of patients, standard colonoscopy examination is necessary and returning a enteroscope from cecum should be more than 8 minutes.