The recognition of bronchial anatomic abnormalities represents an important challenge as it can affect the ability to correctly plan bronchoscopic sampling procedures, lung resections, and placement of endotracheal/bronchial stents.1–3 Furthermore, some anomalies can be mistaken for something more sinister and can prompt unnecessary and invasive diagnostic procedures.2 We herein present a complex, rare anatomic variant of the right endobronchial tree characterized by a true agenesis of the right upper lobe and a left vascular isomerism.
A 50-year-old woman awaiting surgery for esophageal cancer was referred for preoperative bronchoscopy. The examination did not reveal any malignant airway involvement yet there was absence of the orifice of the right upper lobe bronchus. The middle lobe bronchus had an abnormally large diameter and presented a supernumerary bronchus arising proximal to the bifurcation into the lateral and medial segmental bronchi (Fig. 1); the supernumerary bronchus was directed upward and bifurcated into 2 very thin branches at 1 cm from its origin. A computed tomography scan confirmed both, the absence of the right upper lobe bronchus and the presence of a supernumerary branch of the middle lobe bronchus which tended to fill the space normally occupied by the upper lobe segmental bronchi (Fig. 2). At right thoracotomy (performed for esophageal resection) only 2 lobes, separated by a single complete lung fissure, could be observed. Furthermore, there was an anomalous branching of the pulmonary artery. The parenchyma of the upper part of the lung was fed by 3 separate branches instead of a single trunk (anterior trunk, ie, Boyden artery) (Fig. 3). The interlobar portion of the pulmonary artery showed a usual-type branching pattern: the artery for the superior segment of the lower lobe, a single artery to the middle lobe and the common basal trunk.
On the basis of this multidisciplinary documentation, we think that this can be regarded as a unique case of pulmonary malformation characterized by a right upper lobe agenesis and a left vascular isomerism.1,2,4 Radiologists, thoracic endoscopists, and surgeons should be aware of this anatomic variant to reliably localize endobronchial lesions and correctly plan possible lung resection.
1. Ghaye B, Szapiro D, Fanchamps JM, et al. Congenital bronchial abnormalities revisited. Radiographics. 2001;21:105–119.
2. Zylak CJ, Eyler WR, Spizarny DL, et al. Developmental lung anomalies in the adult: radiologic-pathologic correlation. Radiographics. 2002;22:S25–S43.
3. Wu JW, White CS, Meyer CA, et al. Variant bronchial anatomy: CT appearance and classification. AJR. 1999;172:741–744.
4. Read R, St Cyr J, Marek J, et al. Bronchial anomaly
of the right upper lobe. Ann Thorac Surg. 1990;50:1980–1981.