eP563 - A Diagnostic Dilemma: A Rare Case of a Large Bowel Obstruction Secondary to Urothelial Carcinoma

Purpose/Background: Urothelial carcinoma is a malignancy of the urogenital tract that typically arises from transitional cells. When advanced, it can metastasize to other parts of the body such as the liver, lungs, lymph nodes and bones. Furthermore, they can infiltrate or spread to surrounding organs. There are a few reports in the literature describing urothelial carcinoma infiltrating into the rectum, but when they do happen they typically do with a known primary bladder malignancy. In this case, we describe a 69 year old man who presented with vague abdominal pain and fatigue. His work-up revealed an acute kidney injury with bilateral hydronephrosis, cystitis, proctitis and dilated colon. He ultimately was diagnosed with a rectal stricture secondary to high-grade urothelial carcinoma infiltration of unknown origin.Methods/Interventions: This patient underwent a cystoscopy which revealed a very inflamed and contracted bladder that poorly distended. Ureteral orifices could not be visualized. He ultimately underwent bilateral nephrostomy tube placement and ureteral stents. A flexible sigmoidoscopy was performed which revealed an extrinsic rectal stricture without any intraluminal lesions. Biopsies came back as negative for malignancy. He then underwent a diverting colostomy. A repeat flexible sigmoidoscopy in attempts of obtaining a pathological diagnosis was once again non-diagnostic. A paracentesis was performed and cytology was also negative for malignant cells. He was then eventually taken to the operating room for a rectal examination under anesthesia which revealed a progressively enlarging and infiltrating anorectal mass. A 1 cm incisional biopsy was obtained which revealed a high-grade urothelial carcinoma. Tumor markers revealed a CEA of 6.5, PSA of 0.2 and CA-19-9 of >20,000.Results/Outcomes: Patient's hospital course was complicated by ureteral stent occlusion and urinary tract infection requiring prolonged antibiotics, C. diff infection, ileus, and lower extremity DVTs requiring anticoagulation. Furthermore, patient continued to develop recurrent ascites requiring frequent paracentesis. Plans for repeat cystoscopies were discussed with the patient in order to try to obtain a primary malignancy diagnosis; however, given the advanced nature of the patient's disease, patient opted to pursue hospice care.Conclusion/

Discussion: Urothelial carcinoma of the bladder is the ninth most common cancer in the world with a male predominance and majority being diagnosed over the age of 65. Five year survival rates can be up to 80% when disease is limited to the bladder, but drops to 5% when metastasis develop; thereby, stressing the importance of an early diagnosis. Typical diagnosis involves urinalysis, urine cytology, cystoscopy and CT or MRI imaging. When advanced, these cancers can infiltrate nearby organs such as the prostate, urethra, ureters, vagina or uterus. There are a few case reports of urothelial carcinoma invading or metastasizing to the rectum. At advanced stages, treatment typically is aimed at palliative chemotherapy and/or radiation. This case report highlights the need to having a high index of suspicion of a urogenital tract malignancy when presenting with extrinsic rectal compression and genitourinary findings such as hydronephrosis and cystitis as this can indicate a primary urogenital tract malignancy. Efforts should focus on bypassing the GI obstruction and identifying the primary malignancy to target therapies."CT scan demonstrating rectal narrowing causing a large bowel obstruction.

CT scan further demonstrating a large bowel obstruction secondary to a rectal stricture.

Colonoscopy revealing an extrinsic stricture of the rectum.