Acquired Pulmonary Arteriovenous Fistula within Metastasis from Choriocarcinoma: A Case Report.

Choriocarcinoma is a highly malignant neoplasm arising from the trophoblast of a human pregnancy, which may have distant spread to multiple organs, particularly to the lung. We report a case of a pulmonary arteriovenous fistula that developed after chemotherapy within a choriocarcinoma metastasis. A 24-year-old female with a history of uterine choriocarcinoma presented with multiple hypervascular pulmonary nodules on the initial chest computed tomography (CT) scan, consistent with lung metastases. Four months after chemotherapy, follow-up chest CT revealed a decrease in the size and vascularity of the lung metastases, except for 1 nodule that persisted with marked contrast enhancement and developed a communication with a pulmonary artery and vein. These findings were consistent with an acquired arteriovenous fistula. Physicians should be aware of the risk of acquired arteriovenous fistula in pulmonary metastases after chemotherapy because it can lead to a right-to-left shunt, pulmonary hemorrhage, and paradoxical emboli. It is also important for the definition of therapeutic planning, in order to avoid it being misdiagnosed as a site of disease progression.