CASE 16599 Published on 12.02.2020

Scimitar Syndrome – the pathognomonic imaging finding

Section

Cardiovascular

Case Type

Clinical Cases

Authors

Pedro Marques, Ana Germano, Pedro João

Radiology Department – Hospital Prof. Doutor Fernando Fonseca, IC 19, 2720-276 Amadora, Portugal.

Patient

71 years, male

Categories
Area of Interest Anatomy, Cardiovascular system, Thorax ; Imaging Technique CT, CT-Angiography, Digital radiography
Clinical History

A healthy 71-year-old man presented to the emergency department with fever (39°C), mucopurulent productive cough and diffuse myalgia. The patient was treated symptomatically and discharged. The patient returned 4 days after with the same symptoms and increased inflammatory parameters. A respiratory infection was assumed and he was medicated with antibiotics.

Imaging Findings

Both Chest X-ray and Chest computed tomography (CT) were done.  The Chest X-ray showed a vertical tubular structure, with crescent morphology in the right hemithorax. The Chest CT proved the existence of a curvilinear soft-tissue density structure, following a convex curve to the left in the right pulmonary parenchyma and reaching the diaphragm in its medial part. In a later CT, following contrast media administration, it was evident the vascular nature of this curvilinear structure. At that time, bilateral pleural effusion and atelectasis of adjacent pulmonary segments were also observed. Multiplanar reconstructions demonstrated the course of this anomalous vein, which descends into the lung, posteriorly and medially, to finally drain into the inferior vena cava (IVC), just below the diaphragm. Imaging thus evidenced an abnormal intra-pulmonary vein with drainage into the IVC. Hypoplastic right lung, ipsilateral mediastinum deviation and contralateral lung compensatory hyperinflation were also identified.

Discussion

Scimitar syndrome, or hypogenetic lung syndrome, is one of the several types of partial anomalous pulmonary venous return and is one of the findings of congenital pulmonary venolobar syndrome. This congenital anomaly is characterised by a hypoplastic lung, drained by an anomalous vessel into the systemic circulation, a pathognomonic aspect of this syndrome. The anomalous pulmonary vein can drain into the IVC, directly on the right atrium or into the portal vein. This left-to-right shunt occurs exclusively on the right side and typically has a path parallel to the right cardiac border, resembling the shape of the Turkish sword (scimitar) blade, hence its name [1,2]. Regarding the clinical presentation, children present with signs of heart failure because they usually have associated cardiac congenital abnormalities. Adults are asymptomatic or present with exertional dyspnoea or recurrent respiratory infections. The scimitar syndrome can be associated with several other abnormalities, such as congenital heart disease, horseshoe lung, pulmonary sequestration, ipsilateral diaphragmatic anomalies, genitourinary tract abnormalities and vertebral anomalies [3]. The diagnosis of scimitar syndrome is radiological, mostly incidental. The pathognomonic imaging finding is the anomalous pulmonary vein establishing a communication between the systemic and pulmonary circulations, associated with a hypoplastic right lung. Usually, no treatment is required, unless there is severe pulmonary hypertension or significant symptoms [4].

Written informed patient consent for publication has been obtained.

Differential Diagnosis List
Scimitar syndrome
Meandering right pulmonary vein
Swyer-James-MacLeod syndrome
Pulmonary varicose vein
Final Diagnosis
Scimitar syndrome
Case information
URL: https://www.eurorad.org/case/16599
ISSN: 1563-4086
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