Isolated pulmonary artery choriocarcinoma masquerading as pulmonary embolism diagnosed by endovascular biopsy.

Pulmonary arteries may rarely be involved by primary and secondary tumors. Clinical and imaging features mimic those of PE making it challenging to diagnose. Choriocarcinoma is a malignant germ cell tumor, typically in the female genital tract. Rarely, they can present as PA thrombus. Female patients with a history of a molar pregnancy, ectopic pregnancy, abortion or in this case a miscarriage, are at a higher risk of gestational trophoblastic disease which can manifest in this way, albeit this is rare. In this report we describe the case of a 52-year-old female who presented with a 1 month history of worsening dyspnea and pleuritic lower thoracic pain. A diagnosis of pulmonary embolism (PE) was confirmed on CT pulmonary angiogram, with a large volume thrombus in the left pulmonary artery (PA). She failed to improve on standard anticoagulation therapy and was found to have a raised beta-human chorionic gonadotropin of >100,000. This leads to an extensive malignancy work-up. The only pertinent finding was that of increased fluorodeoxyglucose (FDG) accumulation in the PA thrombus. Endovascular biopsy of the thrombus was performed, and the patient was diagnosed with choriocarcinoma of the PA. This case highlights the importance of further investigation in patients failing to respond to anticoagulation therapy for PE. It also illustrates the role of interventional radiology in obtaining histological diagnosis in patient's presenting with PA tumor thrombus.