Explosive rise of serum CA 125 following the rupture of ovarian endometrioma.

Serum CA 125 concentration is seldom >100 IU/ml in endometriosis. We report a patient with ruptured endometrioma presenting with a very high CA 125 concentration, 9300 IU/ml. Elimination of endometriosis was followed by a sharp decrease in serum CA 125. We conclude that some of the CA 125 molecules from the ruptured endometriotic cyst may be transferred through the peritoneum, thereby increasing serum CA 125 concentration. The associated inflammatory reaction of the mesothelial cells of the peritoneum was probably the most important contributor to this phenomenon, as mesothelial cells are an important source of CA 125.