A 55-year-old male presented to the Accident & Emergency Department of the Armed Forces Hospital, Muscat, Oman, in 2012 with increased micturition, dysuria, bilateral loin pain and progressive bilateral lower limb swelling. Two months previously, he had undergone an open radical prostatectomy with open pelvic lymph node dissection for an adenocarcinoma with a Gleason score of 7 (3 + 4). There was no other relevant prior medical history. On physical examination, the patient was afebrile with normal vital signs. An abdominal examination revealed a 7 cm vertical healed surgical scar in the midline suprapubic region with lower abdominal tenderness. Mild bilateral pitting pedal oedema was noted. All preliminary routine investigation results were within normal limits. Ultrasonography and non-contrast computed tomography (CT) of the kidney and urinary bladder region revealed two large well-defined cystic lesions in the lower pelvis, along the inner aspect of the iliopsoas muscles.