Markedly elevated β-hCG levels in a normal singleton gestation with hyperreactio luteinalis

BACKGROUND: Human chorionic gonadotropin (hCG) is produced by the trophoblast early in pregnancy and peaks at a level of approximately 100,000 IU/liter around the ninth week of gestation. Abnormally high levels are usually noted in association with multiple gestation, molar gestation, and specific ovarian or gestational malignancies. CASES: A multiparous patient in the second trimester was referred for evaluation after a maternal triple marker screen was incalculable due to a beta-hCG level of 2.1 million IU/L. Targeted sonography revealed bilateral complex adnexal masses with a solid component of the left ovary, a normal fetus, and normal placenta. The patient underwent an exploratory laparotomy at 18 weeks' gestational age. A left oophorectomy was performed. Pathology confirmed hyperreactio luteinalis. The remainder of the pregnancy was remarkable for preterm labor and delivery at 35 weeks' gestational age. At delivery, the hCG level was noted to be 24,210 IU/L, and the fetus and placenta were normal. CONCLUSION: Markedly elevated hCG levels rarely occur in normal singleton pregnancy and can be associated with hyperreactio luteinalis. When noted, a work-up to evaluate possible malignancy, molar gestation, and multiple gestation should be pursued.