Severe Rectal Stenosis as the First Clinical Appearance of a Metastasis Originating from the Bladder: A Case Report and Literature Review.

While locally advanced rectal cancer is the first clinical suspicion for severe rectal stenosis, in extremely unusual cases a lower bowel obstruction may be related to bladder metastasis. We present the case of a 64-year-old male who was admitted for occlusive rectal tumor (4 cm from the anal verge), for which an emergency loop-colostomy was performed. After two inconclusive endoscopic biopsies, a transanal rectal tru-cut biopsy allowed for the detection of high-grade urothelial carcinoma with signet ring cells. Furthermore, primary origin was detected in a small bladder tumor. In imaging reassessment after neoadjuvant chemotherapy, regression of the lesions both from the bladder and rectum was observed. Radical surgery with total pelvic exenteration was considered in the absence of other secondary tumors, but the patient declined and continued with radiotherapy. Subsequently he developed malignant chylous ascites and unfortunately died three months later. Reviewing the literature, we found twenty-five cases of urothelial metastasis to the rectum, originating from the bladder, including this newly present case. Rectal metastasis of urothelial origin poses a two-fold challenge in terms of both diagnosis and treatment. Determining the specific features of this uncommon manifestation of a common disease will improve future approaches.