Lobectomy for Anomalous Systemic Arterial Supply to the Basal Segment of the Lung in the Second Trimester of a Pregnant Patient with Hemoptysis

An anomalous systemic arterial supply to the basal segment of the lung (ABLL) is a rare congenital vascular anomaly. We herein report a case of ABLL in a 26-year-old pregnant woman with hemoptysis. Contrast-enhanced chest computed tomography (CT) revealed an abnormal vessel branching directly from the descending aorta and circulating to the left lower lobe while showing a normal bronchial anatomy. The patient was therefore diagnosed with ABLL. Maternal safety was a priority, and the patient underwent thoracoscopic left lower lobectomy at 19 weeks' gestation. We concluded that the hemoptysis had been caused by an increased circulating plasma volume during pregnancy.