Abnormal anastomosis of peripheral pulmonary arteries, initially suspected to be an arteriovenous fistula, in an adult with Williams syndrome.

Abnormal anastomosis of peripheral pulmonary arteries is rare and resembles a pulmonary arteriovenous fistula; thus, when the inflow or outflow route cannot be clearly identified in a suspected pulmonary arteriovenous fistula, the possibility of peripheral pulmonary artery anastomosis should be considered. However, the final diagnosis requires a catheterization study.

Clinical Image

A 45‐year‐old man with Williams syndrome, who was being followed up for supravalvular aortic stenosis, underwent a computed tomography scan with a suspicion of pneumonia, which was not observed by radiography because of fever and cough. He was suspected of having a right pulmonary arteriovenous fistula, wherein A10b forming the loop appeared to run near A6 and flow into the upper pulmonary vein. Nevertheless, the possibility of its connection with A6 or the bronchial artery was not excluded (Fig. 1). Angiography findings revealed that the loop was an abnormal anastomosis from A6c to A10b (Fig. 2). Williams syndrome is a congenital multisystem disorder occurring in approximately one in 10,000 live births. Peripheral pulmonary artery stenosis is present in 40% of the patients with Williams syndrome [1]. In this case, basal pulmonary artery was narrowed (Fig. 3). Considering that the blood flow from A6c was superior to that from A10b in the loop, this abnormal anastomosis might have been a bypass from A6c to A10b that formed as a compensation for poor blood flow in the basal lung. Therefore, we decided to observe the patient, without performing coil embolization. Peripheral pulmonary artery stenosis will be treated, if necessary, during the follow‐up period.

Figure 1

The 3D computed tomography scan shows right A10b forming a 3‐mm‐diameter loop. It is unclear whether the loop is connected to A6, the RSPV, or a tortuous and dilated BA. 3D, three dimensional; BA, bronchial artery; RSPV, right superior pulmonary vein.

Figure 2

Pulmonary angiography with contrasting right A10b shows the loop; the contrast agent was pushed back without flowing into the pulmonary vein (A, B). Pulmonary angiography with contrasting right A6c shows A10b and the loop (C, D). Arrowheads: vascular loop.

Figure 3

The 3D computed tomography and angiography findings show significant narrowing of the right basal PA. Arrowheads: PA stenosis. 3D, three dimensional; PA, pulmonary artery.

Disclosure Statement

Appropriate written informed consent was obtained for publication of this case report and accompanying images.

Author Contribution Statement

Hironori Oyamatsu contributed to the writing of this manuscript. All authors treated the patient and approved the final manuscript.