• A 75-year-old male patient presented to the pain clinic with bilateral hip and lumbosacral pain.  At the same time, he presented to the colorectal surgeons reporting rectal bleeding and a change in his bowel habit. A pulsatile mass within the pelvis could be felt on digital rectal examination.
• Relevant past medical history: This patient was involved in a road traffic accident 25 years previously requiring significant vascular and bony reconstruction. Large amount of metalwork were noted on plain x-ray of the pelvis. The hip joints showed moderate arthritis on plain x-ray, more so on the left than on the right.

Apart from moderate osteoarthritis, what else do you note?

An MRI scan of his pelvis was requested, see images below. What do you notice?

• There is considerable artefact from metalwork in the lower right pelvis.
• There appears to be something causing extrinsic mass effect upon the rectum, however the gross artifact (reflection from the metal work) obscures detail.

Further Steps:

• What do you think could be causing the mass effect?
• A CT scan was requested to further evaluate this patient. See images below.