Appendicovesical fistula presenting as a bladder mass in a girl with cystic fibrosis: a case report

Appendicovesical fistula in patients suffering from cystic fibrosis is a rare condition. Although this situation is so rare it should be considered in the differential diagnosis, dealing with a patient with cystic fibrosis and chronic abdominal pain with no response to primary management. To the best of our knowledge, this is the third case of appendicovesical fistula in a patient with cystic fibrosis.

In this paper, we are reporting a bladder lesion of a nine-year-old Iranian girl, a known case of cystic fibrosis, who was referred to pediatric urology clinic, Children’s Medical Center, Tehran University of Medical Sciences. The girl is a known case of cystic fibrosis on regular follow-up who had chronic abdominal pain for about one year. While primary management had been failed for her, further workups were done by her pediatric pulmonologist. In her pelvic sonography, the radiologist reported a bladder lesion so she was referred to our clinic. Cystoscopy was done for her, but transurethral biopsy/resection was impossible according to the lesion location. The non-papillary nature of the lesion raised our concern about the possibility of genital rhabdomyosarcoma with bladder invasion. So, an Abdominopelvic CT scan and a pelvic MRI were also done for her. Intact uterus and vagina with an enhancing lesion at the dome of the bladder with some degree of inflammation/attachment around the adjacent GI tract were detected on her images. The urachal inflammatory/tumoral process could not be ruled out. So open surgical exploration was planned. During the attempt for surgical exploration and partial cystectomy, at the Children’s Medical Center in December 2021, we found that the mass, is actually her appendix which has invaded the urinary bladder, and presented as a bladder lesion.

Abdominal pain is a relatively common complaint of patients with cystic fibrosis. Every caregiver or physician should consider rare conditions, dealing with a cystic fibrosis patient whose abdominal pain does not respond to common management.