Abstract for presentation at Australia and New Zealand Society of Nephrology Annual Scientific Conference

Background: Serum Ca-125 is a sensitive tumor marker that is valuable in the follow up of ovarian malignancy. CA-125 is however nonspecific and is induced by peritoneal irritation leading to mesothelial cell production. A range of benign and malignant conditions with serosal fluid accumulation have been reported to be associated with Ca-125 elevation with no underlying ovarian malignancy. We report a case of spontaneous urinary ascites with markedly raised CA-125 level mimicking ovarian malignancy.
Case: A 47 year old female presented with ascites, oliguric renal failure and hyponatraemia. Her past history was only significant for a total abdominal hysterectomy five years prior. A raised ascitic (1.01mmol/L): serum (0.50mmol/L) creatinine ratio was found on diagnostic paracentesis, highly suggestive of intraperitoneal urine. The ascites resolved spontaneously over days with the insertion of indwelling catheter. The biochemical indices also normalized over 48 hours with no need for dialysis. During the admission, serum CA-125 levels were measured. The level peaked at 685.5 IU/ml raising the concern for possible ovarian malignancy. Repeat abdominal imaging with CT and ultrasound showed no underlying ovarian malignancy. The CA-125 level gradually normalized on follow-up. Urodynamic follow up demonstrated an acontractile bladder that necessitated long term suprapubic catheter. She has since been lost to follow up.
Discussion: This is the first reported case of elevated CA-125 in urinary ascites secondary to neurogenic bladder outlet obstruction. CA-125 should be used judiciously in patients with serosal fluid accumulation, and its clinical role remains that of patient follow up rather than diagnosis.