ODP390 Metastatic Gestational Trophoblastic Neoplasia Masquerading as Thyroid Storm in a Girl with Molar Pregnancy and Hyperthyroidism

Abstract

The Case Patient is a 16-year-old female with molar pregnancy , admitted for D&C, referred for hyperthyroidism, concern for thyroid storm. A month prior, she presented with heavy vaginal bleeding, morning sickness. Ultrasound showed blighted ovum. HCG was significantly elevated, 668,123 mIU/mL. TSH was low at 0. 01 mIU/L, Free T4 elevated 2.3 ng/dL. No family history of thyroid dysfunction. She was for was noted to have respiratory distress , hypoxia, and tachycardia in the 120s post-operatively. LFTs normal, no fever, jaundice or CNS manifestations. Chest CT showed bilateral lower lobe localized pulmonary edema concerning for trophoblastic fluid embolism vs thyroid storm. BWPS = 40. She was placed on PTU, beta blockade , Lugol's iodine, and hydrocortisone. Repeat chest CT showed diffuse pulmonary nodules consistent with gesta-tional trophoblastic neoplasm (GTN). No other metastasis on further imaging (chest, abdomen, pelvis, brain). Clinical status improved, FT4 normalized 5 days after starting treatment. TRAbs negative. She was discharged on Methimazole and Atenolol, which were eventually discontinued. HCG levels significantly decreased after D&C but remained detectable on follow-up. Endocervix/uterine curettage showed intraplacental choriocarcinoma arising within a complete hydatidiform mole. She is followed by Oncology and currently undergoing chemotherapy. Discussion: HCG-mediated hyperthyroidism include ges-tational transient thyrotoxicosis, hyperemesis gravidarum, and trophoblastic hyperthyroidism (TH). Due to significant homology between TSH and the beta-subunit of HCG, HCG can cause hyperthyroidism. 2-60% of women with tropho-blastic disease may have symptomatic hyperthyroidism at time of diagnosis which can be severe. Patients with GTN (choriocarcinoma in our case) have a higher likelihood of TH, as HCG exceeds 100,000 mIU/mL. Choriocarcinoma is the most aggressive type of GTN characterized by vascu-lar invasion and widespread metastases, of which the most common sites are vagina and lungs. Patients with pulmonary metastasis my present with respiratory distress, chest pain, cough or hemoptysis. Our patient was initially thought to have impending thyroid storm mainly from A604 | Journal of the Endocrine Society | https://doi.org/10.1210/jendso/bvac150