An 84-year-old woman diagnosed with rheumatoid arthritis was admitted urgently for abdominal pain and distension. With a diagnosis of subocclusive ileus, medical treatment was initially started. With no urological history, she began a few hours after urethral catheterisation with haematuria, which became very intense, evolving into the formation of a large bladder clot occupying the entire cavity, and perivesical fluid and gas were also observed on computed axial tomography. Urgent surgery was performed, revealing a section of ileum 1.5 m long up to 10 cm from the ileocaecal valve, with a violaceous oedematous appearance, which recovered and acquired a normal appearance, colour and peristalsis; The patient had a small fissure in the bladder wall, so a cystotomy was performed to drain the large clot, observing bleeding in the wall sheet and great friability of the wall, taking multiple biopsies and subsequently performing ligation of both hypogastric tubes. In the immediate postoperative period, after anuria and severe haemodynamic alteration, the patient died (09/05/2000). The anatomopathological diagnosis revealed that all the bladder biopsies performed showed vascular and interstitial amyloid (AA) deposits.