Delayed malignant appendiceal fistula with ileal conduit following radical cystectomy: A case report

Abstract

Fistula formation after radical cystectomy is rare, often presenting early and involving the small bowel. Herein we describe a case of an appendiceal fistula in a patient who underwent chemoradiotherapy and pelvic exenteration over a decade prior to the presentation of their fistula. Initially suspected to be radiation-induced, final pathology revealed a mucinous neoplasm of the appendix, which had fistulized with the ileal conduit. This case emphasizes the importance of considering alternative causes, such as malignancy, in delayed fistulas, especially in patients with prior radiation. Clinicians should maintain high suspicion for appendiceal neoplasms to guide proper preoperative and intraoperative planning.

1 Introduction

Radical cystectomy is associated with significant perioperative and postoperative complications, with up to 60 % of patients experiencing some form of adverse event. Fistula formation following radical cystectomy, though rare, occurs in approximately 0.2–2 % of cases. Several risk factors have been identified as contributing to the development of postoperative fistulas, including poor preoperative nutritional status, diabetes mellitus, previous chemotherapy, and prolonged corticosteroid use. Additional contributing factors may include prior radiation and the use of an orthotopic neobladder for urinary diversion. The most common location for fistulas is between the urinary diversion and small bowel, typically presenting within the first few months postoperatively.

We report a rare case of an appendiceal fistula with an ileal conduit, developing more than a decade after the patient underwent chemoradiation and pelvic exenteration for rectal cancer. Although initial clinical suspicion suggested radiation as the cause, final pathology revealed a low-grade mucinous neoplasm of the appendix that had fistulized with the urinary diversion. This case underscores the importance of considering alternative etiologies for patients with atypical presentations of appendiceal fistulae and maintaining a high index of suspicion for malignancy when encountering delayed fistulas in patients with urinary diversion, especially those involving the appendix.

2 Case presentation

A 73-year-old male with a history of rectal cancer, treated in 2012 with chemoradiotherapy followed by pelvic exenteration with colostomy and ileal conduit, presented in August 2024 with worsening right-sided hydronephrosis, as seen on CT urogram, and an elevated creatinine level. The patient had a known left-sided ureteral stricture, which resulted in a significant decline in his left kidney function (<5 %) on MAG3 lasix renal scan, leaving him with a functionally solitary right kidney.

Given the findings of hydronephrosis, a loopogram was performed to assess for a right-sided ureteral stricture. The loopogram demonstrated high-grade bilateral ureteral anastomotic stenosis and a fistula between the distal left ureter, the ileal conduit, and appendix. A right sided nephrostomy tube was placed for renal decompression ( Fig. 1 ).

Initially, the fistula was presumed to be a delayed complication from prior radiotherapy, originating from the butt end of the conduit and involving the appendix. Imaging also raised concerns about possible involvement of the right common iliac artery in the appendiceal fistula ( Fig. 2 ). Given the potential risk of fistula progression or infectious complications if left untreated, as well as the patient’s desire to live without a nephrostomy tube, reoperative intervention with definitive fistula repair was recommended. Multidisciplinary consultations with vascular and colorectal surgery were conducted preoperatively for surgical planning. Due to loss of fat plane between fistulous area and right common iliac artery, patient was consented for potential iliac artery ligation and femo-femoral bypass.