This 84-year-old woman reports for a CT scan after experiencing right lower quadrant pain. She has a history of a right kidney stone. Can you piece together the somewhat-complex chain of events that has led to her problems? Hint: You might want to start somewhere other than the kidney and look for something that might have a “snowball” effect.
A presumed pelvic mass with soft tissue metastasis into the abdominal/peritoneal cavity is distorting the liver and portions of the bowel. The primary mass also causes blockage/obstruction of her distal left ureter, which is important in this case because the right kidney is essentially non-functioning due to xanthogranulomatous pyelonephritis (XGP).
Other observations include:
- Complex high density collection in the pelvis, likely associated with a primary tumor mass. Mean Hounsfield attenuation of 30.
- XGP. You should also note associated renal atrophy with central Staghorn calculus and the stone in her scarred kidney (red arrow, image 3)
- Dense ascites (circle, image 4)
- Hydronephrosis (arrows, image 5)
- Question: What is the cause of the patient’s right lower quadrant pain?
- 1. Acute diverticulitis
- 2. Perforated appendicitis
- 3. Distal right ureteral stone with renal obstruction
- 4. Carcinomatosis
The answer to the above question is (4) Carcinomatosis (it is seen on image 2). Clinically, she is in renal failure with elevated blood urea nitrogen (BUN) and creatinine, due to an obstructed distal left ureter with multiple peritoneal implants. For more case review, check out MRI Online.
Stephen Pomeranz, M.D.
Nick Trane, M.D.