Resolution of Bilateral Ovarian Theca Lutein Cysts Following Resection of a Functioning Gonadotroph Pituitary Macroadenoma: A Case Report

Functioning gonadotroph adenomas (FGAs) are rare pituitary neuroendocrine tumors (PitNETs) that secrete biologically active gonadotropins, which stimulate ovarian tissue and may result in ovarian theca lutein cysts in women.Because gonadotropin levels are often within normal reference ranges, diagnosis can be challenging and may lead to unnecessary gynecologic interventions.A woman with a recurrent gonadotroph PitNET underwent repeat tumor debulking.Approximately 60 days after surgery, she was found to have abnormal uterine bleeding (AUB), bilateral ovarian theca lutein cysts, and hyperestrogenemia.Pelvic ultrasonography revealed marked bilateral ovarian enlargement with multiple cystic lesions, measuring up to 10.4 cm on the right and 11.7 cm on the left.Laboratory evaluation revealed markedly elevated estradiol levels (496 pg/mL; normal range, 10-300 pg/mL), with an inappropriately normal follicle-stimulating hormone (FSH) level (5.2 mIU/mL; normal range, 3-10 mIU/mL) and suppressed luteinizing hormone level (0.3 mIU/mL; normal range, 2-12 mIU/mL).These findings raised suspicion for an FGA.Subsequent followup demonstrated a decline in estradiol levels and near-complete resolution of the ovarian cysts, with a marked reduction in ovarian size to 4.5 cm on the right and 4.6 cm on the left.This case highlights the importance of considering a FGA in women presenting with bilateral ovarian theca lutein cysts, hyperestrogenemia, endometrial thickening, and AUB.Although the clinical and biochemical findings suggest an association between the pituitary tumor and ovarian hyperstimulation, definitive causality cannot be established because the ovarian abnormalities were first documented after tumor debulking.Recognition of this rare entity may help guide appropriate management and avoid unnecessary ovarian intervention.