Horseshoe lung associated with scimitar syndrome

Imaging spectrum of horseshoe lung: A series of four cases

Horseshoe lung (HL) is a rare congenital anomaly represented by the fusion of both lungs, posterior to the heart, and is typically associated with various bronchopulmonary and cardiovascular malformations. Multi-detector contrast enhanced CT is the imaging modality of choice to demonstrate the pathology and associated malformations. There has been inconsistency in the nomenclature used for such cases in literature. To resolve ambiguity, the authors emphasise that only two terms: HL and pseudo-HL be used on imaging to describe variants of this congenital malformation.

Contribution

A description of the imaging features in four cases of HL, with their associated malformations and a review of the nomenclature.

Diaphragmatic eventration as a first sign of Scimitar syndrome

Diaphragmatic eventration is an anomaly of the diaphragm. In Scimitar syndrome, a curved-shaped anomalous pulmonary venous drainage is seen. Association between these conditions is rare. We present a newborn with diaphragmatic eventration, whose diagnosis of Scimitar syndrome was made after surgical repair. Scimitar syndrome is a congenital disorder often associated with other heart and lungs anomalies. Diagnosis can be fortuitous but with important prognostic features.

Posterior Lung Herniation in Pulmonary Agenesis and Aplasia: Chest Radiograph and Cross-Sectional Imaging Correlation

Objective

To describe the anatomic locations and imaging features of posterior lung herniation in unilateral pulmonary agenesis and aplasia, focusing on radiograph-CT/MRI correlation.

Materials and Methods

A total of 10 patients (seven with pulmonary agenesis and three with pulmonary aplasia, male: female = 1:9, mean age 7.3 years, age range from 1 month to 20 years) were included. Chest radiographs (n = 9), CT (n = 9), and MRI (n = 1) were reviewed to assess the type of lung underdevelopment, presence of anterior and posterior lung herniation, bronchus origin, supplying artery, and draining vein of the herniated lung.

Results

Pulmonary agenesis/aplasia more commonly affected the left lung (n = 7) than the right lung (n = 3). Anterior lung herniation was observed in nine of the 10 patients. Posterior lung herniation was observed in seven patients with left pulmonary agenesis/aplasia. Two patients showed posterior lung herniation crossing the midline but not beyond the aorta, and five patients showed the posteriorly herniated right lower lobe crossing the midline to extend into the left hemithorax farther beyond the descending thoracic aorta through the space between the esophagus and the aorta. This anatomical configuration resulted in a characteristic radiographic finding of a radiolucent area with a convex lateral border and a vertical medial border in the left lower lung zone, revealing a tongue-like projection on CT and MRI.

Conclusion

Posterior lung herniation occurs in unilateral left lung agenesis/aplasia. Approximately 70% of the cases of posterior lung herniation reveal a unique radiolucent tongue-like projection in the left lower lung zone on imaging studies, which is caused by the extension of the posteriorly herniated right lung farther beyond the descending aorta.

Two rare cases of horseshoe lung with scimitar syndrome in Vietnam

Horseshoe lung is a rare, congenital, pulmonary anomaly in which the caudal and basal segments of the left and right lungs are joined together. Most cases of horseshoe lung are associated with scimitar syndrome. Horseshoe lung can be diagnosed using pulmonary angiography, showing that the isthmus of the pulmonary parenchyma crosses the midline into the contralateral side. The isthmus parenchyma is typically supplied by the hypoplastic pulmonary artery. Clinical symptoms, therapeutic methods, and prognosis depend on the incidence of pulmonary hypertension, heart failure, recurrent pneumonia, and other combinations of congenital malformations. In this article, we describe two cases of horseshoe lung associated with scimitar syndrome and pulmonary malformation.