Asynchronous bilateral anastomosis site sigmoid colon cancer after ureterosigmoidostomy: a case report

BACKGROUND We present a case of asynchronously occurring adenocarcinomas 29 and 36 years after ureterosigmoidostomy for bladder cancer, respectively, at both anastomosis sites. CASE PRESENTATION A colonoscopy that was performed on a 69-year-old man because of bloody stool and an elevated carcinoembryonic antigen (CEA) level revealed a polypoid lesion at the right ureterosigmoid anastomosis site 29 years after the patient's ureterosigmoidostomy. Endoscopic resection was performed, and the lesion was diagnosed as adenocarcinoma. Seven years later (36 years after ureterosigmoidostomy), an elevated lesion was detected at the left ureterosigmoid anastomosis site by colonoscopy performed after detection of high CEA levels. Biopsy revealed an adenocarcinoma that was immunohistologically positive for CDX2; sigmoidectomy and ureterectomy were subsequently performed. The pathological diagnosis of the second tumor was adenocarcinoma arising in the ureterosigmoid anastomosis site and invading the left ureter. CONCLUSIONS Diligent long-term follow-up of patients who underwent ureterosigmoidostomy is essential.