Ovarian endometrioma associated with very high serum CA-125 levels

CA-125 is a 220-kD cell surface glycoprotein present in over 80% of non-mucinous epithelial ovarian carcinomas and it occurs in the serum of healthy males and females at low concentrations (< 35 U/mL). Serum CA-125 concentration may also be moderately elevated in several benign conditions, such as pelvic inflammatory disease, uterine fibroids, pregnancy, spontaneous abortion with chromosomal abnormality, and especially in endometriosis. However, serum CA-125 concentration is seldom > 100 IU/ml in endometriosis. In this paper, we present a patient with unilateral ovarian endometrioma associated with abnormally high serum CA-125 level (> 6000 U/mL) and after excision of the ovarian tumor, the CA-125 levels returned to normal. Our case further emphasizes the association of high levels of CA-125 with benign gynecologic conditions and we discussed the possible explanations for this abnormal elevation of CA-125 levels.