Hyperthyroidism in a complete molar pregnancy with a mature cystic ovarian teratoma

Background The hallmark of gestational trophoblastic disease is the production of human chorionic gonadotropin (hCG) due to the hyperproliferation of extraembryonic trophoblast cells. Previous studies show hCG has thyrotropic action due to its structural similarity with thyroid stimulating hormone (TSH) molecules. Germ cell tumors represent 15–20% of all ovarian tumors and can be malignant or benign. Case presentation We present a case of a 53-year old African American female with a history of hyperthyroidism secondary to a complete hydatidiform mole and an associated finding of a mature cystic ovarian teratoma. She presented with nausea, vomiting, nervousness, weight gain, abdominal pain and a b-hCG of greater than 450,000mIU/mL. A total abdominal hysterectomy with bilateral salpingo-oophorectomy was performed and curative for her symptoms. Lung nodules were noted with slight increases in b-hCG levels in the months following the surgery. Propranolol and methimazole were used to treat the acute hyperthyroid symptoms. Conclusion This case presents the rare occurrence of a complete hydatidiform mole causing hyperthyroidism and an associated finding of a mature cystic teratoma. It also highlights the importance of monitoring b-hCG levels following a complete molar pregnancy due to an increased risk of choriocarcinoma.