History and findings: A 39-year-old man was hospitalized because of continually rising urinary creatinine and blood urea nitrogen concentration. He was known to have familial adenomatous polyposis (FAP), first diagnosed 18 years previously and re-Physical examination was unremarkable except for pain on percussion over both kidney regions. There was a well-healed laparotomy scar.
Investigations: Ultrasound revealed chronic bilateral obstructive renal disease, grade II-III, and computed tomography showed a conglomerate retroperitoneal tumour with obstruction of both ureters at the level of the lower pelvis. This tumour had first been noted first 3 years after the colectomy when the patient complained of abdominal pain. It had been identified histologically as a nonresectable retroperitoneal desmoid tumour.
Treatment and course: An external fistula was made, relieving the renal retention. To suppress growth of the desmoid tumour Sulindac, a nonsteroid anti-inflammatory drug, was administered. Genetic molecular analysis revealed a germ line defect in codon 1690 of the APC gene. It is intended to examine other members of the family for the presence of this defect.
Conclusion: Desmoid tumours are more common in persons with FAP and are among the most frequent extracolic causes of their death. Treatment options are critically analysed.