CA-125: What does that lab really mean?

Ovarian torsion is often a diagnosis of exclusion, and while less common in pre-pubertal females, it is on the differential for a pelvic mass. Tumor markers can be used to characterize a pelvic mass, with varying sensitivity and specificity. This is a case of a 10-year-old pre-pubertal female presenting with abdominal pain and found to have an ovarian mass. Her tumor markers demonstrated an elevated CA-125, increasing concern for neoplasm. This led to a delayed operative course and she was ultimately found to have an ovarian torsion. There is unclear utility of CA-125 in pediatrics and reliance on tumor markers during the work-up of an ovarian mass should be limited to avoid diagnostic error.