Severe thyrotoxicosis as initial presentation of gastric choriocarcinoma: a case report

Extragonadal choriocarcinoma is rare and can be associated with hyperthyroidism when producing very high levels of human chorionic gonadotropin.

A 62-year-old Hispanic female presented with a 3-week history of shortness of breath, palpitations, extreme weakness, new-onset hot flashes, and right flank pain. Her physical examination was remarkable for tachycardia, hepatomegaly, hyperreflexia, and tremor; goiter was absent. Laboratory studies revealed increased lactate dehydrogenase, alkaline phosphatase, suppressed thyroid stimulating hormone, very elevated T4, and absent thyroid stimulating immunoglobulin. ¹⁸F-fluorodeoxyglucose positron emission tomography-computed tomography exhibited hepatomegaly with multiple large fluorodeoxyglucose-avid liver masses and a focus of fluorodeoxyglucose avidity in the stomach with no structural correlate. A thyroid scan (^99mTcO ₄ ⁻ ) showed diffusely increased tracer uptake. She was started on propranolol and methimazole. Upon stabilization of severe thyrotoxicosis, upper endoscopy was performed, showing a ~ 5 cm bleeding lesion in the greater stomach curvature body; biopsy was consistent with choriocarcinoma; beta-human chorionic gonadotropin hormone was 2,408,171 mIU/mL. The patient received methotrexate followed by etoposide and cisplatin. Methimazole was titrated down, and upon liver failure the medication was stopped. The thyrotoxicosis was effectively controlled with antithyroid drug and concurrent chemotherapy. At ~ 1.5 months after initial diagnosis, the patient died due to bleeding/acute liver failure with coagulation defects followed by multiple organ failure.

Severe thyrotoxicosis can represent an unusual initial presentation of metastatic choriocarcinoma in the setting of extreme elevation of beta-human chorionic gonadotropin. Primary gastric choriocarcinoma is an aggressive malignancy with very poor outcomes. The co-occurrence of severe thyrotoxicosis with advanced primary gastric choriocarcinoma and imminent liver failure complicates management options.