Right pelvic kidney during intersphincteric resection for locally advanced rectal cancer: a case report

BACKGROUND: Simultaneous occurrence of colorectal malignancy with pelvic kidney has been considered a rare phenomenon. A review of the related literature revealed three previous reports of rectal cancer and pelvice kidney. CASE PRESENTATION: This case report describe the case of 40-year-old Asian man with complaints of bleeding and a feeling of discomfort in his anus. A colonoscopy revealed a raised large multilobulated mass in his rectum. Multiple biopsies of the lesion were done after detecting a tumor in his rectum 4 cm above the dentate line; a diagnosis of rectal adenocarcinoma was made by pathological examinations. Subsequent investigations, carried out by computed tomography (CT) scans, incidentally showed an ectopic pelvic kidney. Because of the progress of the rectal cancer, our patient was a candidate for neoadjuvant radiotherapy. Six weeks after radiotherapy, he underwent total mesorectal excision (TME) surgery maintaining the ectopic kidney after using a coloanal anastomosis for additional curative surgery. A very low anterior resection surgery was performed to maintain the ectopic kidney. Thereafter, adjuvant chemotherapy was performed. CONCLUSIONS: Due to the proximity of the tumor to the pelvic viscera, especially the ectopic kidney, the probability of inadequate abscission of the lesion in surgery and radiotherapy, as well as complications and localized relapse were increased so that the kidney could be maintained. Carrying out careful pre-treatment examinations can result in maintaining an ectopic kidney and its daily conditioned function dependent on the status of the patient, including the proximity of the ectopic kidney to the tumor, anatomical position, and prior damage. The lesson learned from the present case is that radiotherapy and surgery are possible treatments in the presence of pelvic kidney and rectal cancer without incurring renal damage. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1186/s13256-019-2151-3) contains supplementary material, which is available to authorized users.