Teaching Case

An 82 year old female with increasing dyspnoea was admitted to the Emergency Department. A Posterior-Anterior (PA) chest radiograph was obtained, followed by chest computed tomography (CT).

A previously healthy 82 year old woman developed respiratory symptoms with dyspnoea and weakness. She presented to the emergency department because of the worsening of clinical conditions. The patient's history was not relevant. A PA chest radiograph was taken and a right pleural effusion, associated with lung atelectasis, as well as left second arc protrusion and enlarged heart shadow, were evident. A CT scan with contrast media administration was acquired for further evaluation. At CT imaging, a curvilinear, soft tissue density was revealed, describing a left-convex curve in the right lung parenchyma reaching the diaphragm in its medial part. In the axial images following contrast media administration a right atrial and ventricular enlargement was confirmed (Fig 1). In addition, the calibre of the common pulmonary artery and its bifurcations increased, as in pulmonary hypertension. The vascular nature of the curvilinear image was evident after contrast media administration (Fig 2a-d). Multiplanar reconstructions were performed and clearly demonstrated the course of this anomalous vein, which descends into the lung adjacent to the right atrium and curved posteriorly to enter the inferior vena cava below the diaphragm (Fig 3). The right inferior pulmonary vein had a normal course to the left atrium. A volume rendering reconstruction of the right atrium revealed that the right superior pulmonary vein was missing (Fig 4). No other associated anatomical anomalies were present.

The scimitar syndrome, also known as hypogenetic lung syndrome, is a rare congenital disorder with partial anomalous pulmonary venous return, consisting in an anomalous pulmonary vein that drains below the diaphragm in the inferior vena cava, hepatic veins, portal vein or azygos vein [1]. More frequently in the scimitar syndrome an anomalous course and drainage of the right inferior pulmonary vein is present; in our case it is appreciable the rare situation of an anomalous right superior pulmonary vein, with a right inferior pulmonary vein draining normally in the left atrium. In rare cases, the anomalous vein may curve upwards and drain othotopically into the left atrium, and this condition is named “meandering vein” [2]. An incidence of 1-3 out of 100,000 live births is described [3], but the true incidence is unknown because the syndrome can be asymptomatic [4]. The name of scimitar syndrome derives from the scimitar sign, a chest postero-anterior radiograph finding consisting in a curved vascular shadow located to the right of the heart that descends towards the diaphragm [5]. The name, first introduced by Halasz et al. in 1956, is due to its similarity with the Turkish sword produced by the curved vascular shadow of the anomalous vein. In addition to the pulmonary vein, associated anomalies include hypoplasia of the right lung and right pulmonary artery, dextroposition of the heart due to dextrorotation, cardiac malformations, systemic arterial supply to the right lung base and bronchial anomalies [2]. Three types of the syndrome have been described: an adult form characterized by a small shunt and excellent prognosis; an infantile form, characterized by a large shunt, prominent systemic arteries supplying the right lung base, pulmonary hypertension, right heart failure, and overall poor prognosis; and a third form characterizing multiple cardiac ad extracardiac malformations [3, 5]. When isolated, the scimitar syndrome is compatible with normal life, and the development of clinical symptoms is related to the degree of the left-to-right shunt that the anomalous venous drainage causes. This is the reason why the syndrome can remain asymptomatic and be evidenced in the adult age, as in the case that we observed. In such cases, 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 major clinical complications are right cardiac failure, related to abnormal venous draining into the inferior vena cava; pulmonary infection, related to the architectural distortion of the maldeveloped lung; and haemoptysis, related to the anomalous systemic arterial supply of bronchopulmonary sequestration [7].