We read with great interest the case report published in a recent issue of the ARCHIVES.1 Au et al described a 45-year-old woman with severe weight loss and ascites of about 2 months' duration. The abnormal laboratory findings were hypoalbuminemia (16 g/L) and elevated levels of serum cancer antigen 125 (CA-125) (1260 IU/mL) and carbohydrate antigen 19-9 (62.5 IU/mL). Although neither cytological nor microbiological abnormalities were detected in the transudative ascitic fluid, a magnetic resonance imaging scan and a more invasive diagnostic procedure using exploratory laparotomy were performed. No abdominal or pelvic malignancy could be defined to explain the extremely elevated CA-125 levels. The patient was finally diagnosed as having mixed connective tissue disease (MCTD) based on the presence of antinuclear ribonucleoprotein antibody, serositis leading to protein-losing enteropathy, probable Raynaud phenomenon, and the absence of clinical and serological evidence of other autoimmune diseases.
Sevinc A, Sari R, Buyukberber S. Cancer Antigen 125: Tumor or Serosal Marker in Case of Ascites?. Arch Intern Med. 2001;161(20):2507-2508. doi: