A Rare Case of Hyperthyroidism Secondary to a Complicated Molar Pregnancy

Program: Late-Breaking Abstracts
Session: LBS 001-014-Late-breaking Thyroid/HPT Axis III
Saturday, March 7, 2015: 1:00 PM-3:00 PM
Hall D-F, Thyroid (San Diego Convention Center)

Poster Board LBS-009
Sushma Kadiyala and Colleen Rose Digman, MD
University of Florida, Gainesville, FL

Hydatidiform mole (HM) occurs with an incidence of 1:1000 in the United States, however higher rates are noted in Mexico and Southeast Asia. Molar pregnancies are categorized as partial or complete moles, with a complete mole caused by one or two sperm fertilizing a single egg without DNA. Hyperthyroidism is a rare complication of molar pregnancy. We present a case of hyperthyroidism in a woman with a complicated HM.


A 35 year-old Phillipino, P1021 patient presented at 6+1 weeks gestation with vaginal bleeding, severe nausea, sinus tachycardia, diaphoresis, and fine tremors. Laboratory findings showed elevated liver function tests and β-hCG (910592 mIU/mL) Trans-abdominal ultrasound documented an enlarged 23-week uterus with a solid collection of echoes and numerous anechoic spaces, as well as clusters of swollen trophoblastic villi consistent with a complete HM. Karyotype analysis confirmed a 46XX diploid. Thyroid function panel on presentation was: TSH 0.01 mIU/L, fT4 >7.71 ng/dL, and tT3 444 ng/dL. She was admitted and initiated on methimazole, propranolol and SSKI.  On day 6 the patient underwent dilatation and curettage followed by significant symptom improvement. Postoperatively, her TSH was 0.01 mIU/L, fT4 2.67 ng/dL and tT3 227 ng/dL. She was discharged home hospital day 8 with two additional days of methimazole and propranolol.

In follow-up, TFTs normalized however hCG rebounded 2 weeks postoperatively, prompting empiric treatment with methotrexate. By 6 weeks, slowly declining hCG levels prompted a CT scan that demonstrated an enhancing heterogeneous mass involving the fundal endo/myometrium with associated pulmonary nodules concerning for choriocarcinoma. At 4 months follow-up, hCG levels continue to trend down (10015mIU/mL) and the patient remains asymptomatic on methotrexate with the potential for initiation of  dactinomycin if levels do not reach zero.


Hyperthyroidism is a rare complication of molar pregnancy. Increased suspicion is warranted in woman of childbearing age, particularly amongst those of Mexican and Asian decent. The majority of HMs are benign, however some cases may be due to choriocarcinoma. Lack of HCG normalization is concerning for persistent trophoblastic disease and/or choriocarcinoma. This case underscores the importance of complete pathologic, biochemical, and if necessary radiographic follow-up to verify resolution.

Nothing to Disclose: SK, CRD

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