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Scimitar syndrome

Dr Yuranga Weerakkody and Dr Frank Gaillard et al.

Scimitar syndrome (also known as pulmonary venolobar syndrome or hypogenetic lung syndrome) ⁴is characterised by a hypoplastic lung that is drained by an anomalous vein into the systemic venous system.

Pathology

It is essentially a combination of pulmonary hypoplasia and partial anomalous pulmonary venous return (PAPVR). It almost exclusively occurs on the right side.

Haemodynamically, there is an acyanotic left to right shunt. The anomalous vein usually drains into

IVC : most common
right atrium or
portal vein

The lung is frequently perfused by the aorta, but the bronchial tree is still connected and thus the lung is not sequestered.

Associations

congenital heart disease (e.g. ASD, VSD, tetralogy of Fallot, PDA)
ipsilateral diaphragmatic anomalies (e.g. accessory diaphragm, diaphragmatic hernia
localised bronchiectasis
horseshoe lung
vertebral anomalies (e.g. hemivertebrae⁴⁾
genitourinary tract abnormalities⁴

Radiographic features

The diagnosis is made by transthoracic or transesophageal echocardiography, angiography, or by CT or MR angiography.

Plain film

Chest radiographic findings are that of a small lung with ipsilateral mediastinal shift, and in one third of cases the anomalous draining vein may be seen as a tubular structure paralleling the right heart border in the shape of a Turkish sword (“scimitar”). The right heart border maybe blurred.

Complications

A potential complication that could develop is development or pulmonary hypertension an Eisenmenger physiology.

Treatment

Surgical correction should be considered in the presence of significant left to right shunting and pulmonary hypertension. This involves creation of an inter-atrial baffle to redirect the pulmonary venous return into the left atrium. Alternatively, the anomalous vein can be re-implanted directly into the left atrium.