Localised retroperitoneal amyloidosis mimicking retroperitoneal fibrosis: a rare cause of obstructive uropathy

Primary localised amyloidosis involving the retroperitoneum is a rare disease. We report a 71-year-old diabetic man who presented with generalised fatigue, malaise and elevated serum creatinine. Investigations confirmed obstructive uropathy secondary to a retroperitoneal mass behind the urinary bladder, causing extrinsic compression of both the ureters, resulting in bilateral hydroureteronephrosis. Following initial bilateral percutaneous nephrostomies to stabilise renal function, a computed tomography-guided biopsy of the pelvic lesion which was done, was suggestive of amyloidosis. We present this case due to the rarity of localised retroperitoneal amyloidosis as a cause of obstructive uropathy.