Teaching Case

A patient was presented for a routine check-up and no clinical problem was found to exist.

The patient was referred to our department for a routine check-up without any clinical problem. The patient’s history was also clear. A Posterior-Anterior (PA) chest radiograph was taken and a curvilinear tubular, soft tissue density parallel to the right heart border was revealed (Fig. 1). Scimitar syndrome was considered the most likely diagnosis. Computed Tomography (CT) was performed for a further evaluation of the lesion. Plain CT and contrast enhanced CT (Fig. 2) confirmed the vascular nature of the lesion and formed the basis for the diagnosis. Sagittal reconstruction of CT images with a contrast agent (Fig. 3) clearly demonstrated the course of this anomalous vein, which descends vertically into the lung and curved frontally to enter the inferior vena cava (IVC) below the diaphragm (Fig. 4). No other associated anomalies were revealed.

The scimitar syndrome [also known as the hypogenetic lung syndrome, epibronchial right pulmonary artery syndrome (Richter K. et al, 1967) or mirror image lung syndrome (Dalith F. and Neufeld H., 1960)] is a rare, complex, congenital disorder almost exclusively affecting the right lung. (1) It was first described by Cooper and Chassinat in 1836. (2) The term congenital venolobar syndrome was first intro duced by Felson B. in 1972. (3) The incidence is estimated to be 1–3 per 100,000 births; however, the true incidence is unknown as the syndrome can remain asymptomatic. (2) The term “scimitar syndrome” [first introduced by Halasz et al. in 1956 due to its similarity with the Turkish sword (Fig 5)] implies the presence of an anomalous pulmonary vein with drainage below the diaphragm (IVC, hepatic veins, portal vein or azygos vein). In rare cases, it directly enters into the right atrium or coronary sinus. (1, 4, 5) The most common components of the congenital pulmonary venolobar syndrome are hypogenetic lungs and anomalous pulmonary venous return (1, 5) Other less constant components are anomalous arterial supply of the right lower lung, smaller or absent right pulmonary artery, horseshoe lung, sequestration, tracheobronchial abnormalities (tracheal stenosis or diverticulum, bronchiectasis), accessory diaphragm, hepatic herniation and rarely absent IVC. (1, 4) Approximately 25% of patients present with congenital heart disease, most commonly septal defects. (2, 4) When isolated, scimitar syndrome is compatible with normal life, as a left to right shunt is not of clinical magnitude. (1, 4) It is usually detected incidentally and needs no therapeutic intervention. In cases of associated abnormalities and severe clinical problems, operative repair is considered mandatory. The preoperative assessment includes some form of angiography (DSA, CTA or MRA) for a detailed evaluation of pulmonary arteries and veins. Finally, surgical reconstruction of any congenital anomaly and re-implantation of the abnormal vein directly to the left atrium may be performed.