Clinical characteristics of 4 children with azygos lobe

Authors

Abstract

Introduction Normally, the azygos vein is localized in the posterior part of the upper lobe of the right lung. Still, during the process of embryogenesis, the azygos vein passes through the upper lobe of the lung. As a result of the parietal and visceral pleura being pulled together during this process, the azygos lobe is formed. The clinical features of the azygos lobe in children have not been summarized so far.
Case Presentation This paper describes the presence of an azygos lobe in 4 pediatric patients presenting with cough and/or wheezing. Additionally, no patho- logical conditions such as bronchiectasis, pneumothorax, or neoplasm associated with the azygos lobe were observed in the evaluated patient series.
Conclusion The azygos lobe does not require specific treatment unless it leads to clinically significant disease. However, to prevent misdiagnosis in radiological evaluations, clinicians should consider this anatomical variation.

Keywords

Introduction

The azygos lobe is a congenital variation of the lung, and its prevalence in the general population has been reported to be approximately 0.2–1.2% [1]. Normally, the azygos vein is located posteriorly in the upper lobe of the right lung; however, during the embryogenesis process, the azygos vein arch is displaced into the right lung and alters the normal relationship between the medial aspect of the right lung, located next to the azygos fissure, and the right side of the mediastinum [2]. The azygos lobe has been reported to resemble various pathological conditions, which can lead to misdiagnosis and incorrect treatment in adults, creating difficulties during thoracic surgeries. For example, an azygos lobe may be mistaken for a bulla, abscess, tumor, or localized pneumothorax [2, 3].
While the clinical characteristics of the azygos lobe in adults are well defined, the clinical implications of this variation in children are more ambiguous, and systematic analyses are limited. This study presents the clinical features of four pediatric patients diagnosed with an azygos lobe at our clinic over the past five years.

Case Presentation

The demographic and clinical characteristics of the four patients with an azygos lobe are summarized in Table 1. Additionally, the postero-anterior chest X-rays are shown in Figure 1.
Ethical Approval
This study did not require ethics committee approval.

Discussion

In the early phases of fetal development, the right posterior cardinal vein, which eventually becomes the azygos vein, is positioned next to the apex of the right lung. Typically, this vein shifts above the lung and settles in the area between the right upper lobe and the main stem bronchi. However, in individuals with an azygos lobe, the vein extends into the right upper lobe, carrying with it four layers of pleura. As a result, a section of the right upper lobe becomes enclosed between this new fissure and the mediastinum, forming what is known as the azygos lobe [4].
The azygos lobe is usually discovered incidentally during a chest X-ray or thoracic CT scan, as seen in our patients. The azygos lobe tends to be asymptomatic and does not present with symptoms in most cases. However, in some instances, it may lead to misinterpretations and be mistaken for lung infections Table 1. Demographic and clinical characteristics of the patients or other pulmonary pathologies [5].
A review of the current literature reveals that the clinical features of the azygos lobe are mostly described in adult case reports. Some studies suggest that the azygos lobe is not predisposed to diseases. However, Ndiaye et al. have noted that if the fissure is deep enough to compress the bronchus draining the azygos lobe, it could lead to atelectasis or bronchiectasis [6].

Limitations

This study has several limitations. First, it is a single-center, retrospective case series involving only four pediatric patients, which limits the generalizability of the findings. Second, the relatively short follow-up period and limited clinical data restrict the ability to assess long-term outcomes and potential complications associated with the azygos lobe in children. Further large-scale, prospective studies are needed to better understand the clinical significance of the azygos lobe in the pediatric population.

Conclusion

The clinical features of the azygos lobe in children have not been well documented until now. In this study, it was incidentally identified in four pediatric patients with respiratory symptoms such as cough and wheezing, without any associated pathological conditions like bronchiectasis, pneumothorax, or neoplasm. Although the azygos lobe is a rare anatomical variant and typically asymptomatic, recognizing it is important to avoid radiological misinterpretation and unnecessary interventions.
Greater awareness among clinicians, especially radiologists and surgeons, is essential, and further pediatric-focused research may help clarify its clinical relevance.

References

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