A Rare Case of an Azygos Lobe in the Right Lung of a 40-year-old Male

Abstract

The azygos lobe is a rare anatomical variant, most often encountered in the right lung. Its etiology is related to a defect of the migration of the azygos vein during the embryonic development. Here, we describe a rare case of an azygos lobe of the right lung, diagnosed incidentally on a computed tomography (CT) scan in a 40-year-old male patient who presented with chest pain, shortness of breath, and fever. The initial differential diagnosis included acute myocardial infarction, aortic dissection, and myocarditis. Chest CT with contrast matter demonstrated a peculiar finding in the right lung which was recognized as an azygos vein passing through the upper lobe and separating an azygos lobe with its mesoazygos. The azygos lobe may be rarely associated with neoplastic processes or spontaneous pneumothorax and its differential diagnosis on imaging studies includes various conditions. Knowledge of this variation is important to avoid misdiagnosis or complications during thoracic surgery.

Variations in the Morphology of Human Lungs and its Clinical Implications

“…This results in the detachment of the upper and of the medial portion of the upper lobe of the right lung located medial to the accessory fissure just above the hilum, resulting in the azygos lobe. [13][14][15] However, we did not encounter an azygos lobe in our study.…”

Azygos lobe: A rare case

“…Radiologic identification is important and azygos lobe should be considered in the differential diagnosis of possible problems during lung surgery and its similarity to other pathologies of the lung. [10] In conclusion, although they are rarely seen in chest X-ray or tomography fatigue, physicians should consider azygos lobe among the differential diagnoses of lung pathologies.…”

The rare anatomical variant of upper lobe: clinical features of 46 cases with surgical procedure

“…The position of the azygosarch is higher than normal one [11]. The visceral and parietal layers ofpleura forming the mesoazygos are not fused, as is shown by thecommon occurrence of pleural effusion extending into the azygos ssure [12,13]. This statefavors mobility of the azygos vein and enables it to jump from itsusual position in the ssure and migrate to the mediastinum [14].…”

“…The presence of an azygos lobe is considered a complicatingissue, especially in cases with hyperhidrosis or spontaneouspneumothorax. An azygos lobe might have a protective effect againstthe improvement of spontaneous pneumothorax reported from somestudies [3,12,14]. Threemechanisms were offered: the re ected pleura might be limiting thesize of a potential pneumothorax; the mechanical stressestransferred to the apex of the lung will be lessening with themeso-azygos; or the changed anatomy may essentially shield againstbullae formation.…”