Ann Thorac Surg 2005;79:331-334
© 2005 The Society of Thoracic Surgeons
Case report
Congenital Absence of the Right Upper Lobe Bronchus With Double Segmental Tracheal Bronchi
Gabriele Di Luozzo, MDa,
Heung Bae Kim, MDa,
Phillip M. Boiselle, MDa,
Andrew A. Colin, MDa,
Steven J. Fishman, MDa,*
a Department of Surgery and Division of Pulmonary Medicine, Boston Children's Hospital, Boston, Massachusetts, USA, Departments of Surgery and Radiology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts, USA
Accepted for publication August 6, 2003.
* Address reprint requests to Dr Fishman, Department of Surgery, Boston Children's Hospital, 300 Longwood Ave, Fegan 3, Boston, MA 02215, USA
steven.fishman{at}tch.harvard.edu
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Abstract
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A multidisciplinary approach revealed an absent right upper lobe bronchus and atretic bronchioles in a child with recurrent pulmonary infections. Use of a multidimensional computed tomographic scan and bronchoscopy clearly delineated the anatomical aberration. The child underwent an uncomplicated right upper anterior segmentectomy with an expedient recovery.
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Introduction
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The development of the bronchopulmonary system begins during the fifth week of intrauterine life and follows a precise, well orchestrated timeline [1]. Variations in development result in a number of anomalies including agenesis, hypoplasia, hyperplasia, or dysplasia [2]. The exact error in the development of the bronchopulmonary tissues dictates the pathologic and clinical significance. The most common encountered bronchopulmonary anomalies include bronchogenic cysts, pulmonary sequestrations, congenital cystic adenomatoid malformations, and congenital lobar overinflation.
In this case report we describe the clinical, radiographic, and bronchoscopic features of a unique congenital bronchial anomaly characterized by absence of the right upper lobe bronchus and stenosis of the right upper lobe segmental bronchus with distal bronchiectasis, resulting in recurrent pulmonary infections.
From infancy through early childhood, this female patient was frequently treated for recurrent pneumonias, asthma, and gastroesophageal reflux. By the age of 17 months, her recurrent pulmonary infections and reactive airway disease prompted investigation for the possibility of cystic fibrosis and immunodeficiency states. She had a normal sweat test. Elevated immunoglobulin E and peripheral eosinophilia were suggestive for allergic sensitivity. Over the course of 18 months between the ages of 5 and 7, the patient had five bouts of recurrent right upper lobe pneumonia despite suppressive antibiotic treatments. Bronchoscopy revealed absence of a right upper lobe bronchus and demonstrated two distinct orifices located approximately 1 cm apart along the lateral aspect of the right main bronchus. The first orifice was presumed to be the origin of the apical segment. The second orifice split immediately into two bronchi, which were thought to represent the anterior and posterior segments. The anterior segment of the right upper lobe was very narrowed with a fish-mouth appearance and contained copious purulent secretions. The secretions had some solid component and brown discoloration suggestive of stagnation (Fig 1). After antibiotic treatment, repeat bronchoscopy with bronchography confirmed the previous anatomic anomalies and demonstrated significant bronchiectasis. However, the extent and distribution of the bronchiectasis was not fully delineated. A noncontrast multidetector helical computed tomographic (CT) scan was performed for more complete characterization. Two-dimensional multiplanar and three-dimensional reconstructions were created from the computed tomography data. These images outlined in detail the extent and distribution of bronchiectasis (Fig 2A) and the relationship of the segmental bronchi (Fig 2B). With regard to the bronchial anatomy, the anterior and posterior segmental bronchi of the upper lobe shared a common ostium and immediately bifurcated. The anterior segment bronchus was diminutive at its origin and demonstrated saccular bronchiectasis distally. The bronchiectasis was limited to the anterior segment.
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Fig 1. Intraoperative rigid bronchoscopy confirming anatomical landmarks. (A) Clear division of the segmental bronchi off the right main bronchus demarcated as the right anterior and posterior bronchi (RA/P), right middle lobe bronchus (RML), and right lower lobe (RLL). (B) More proximal view of the right main bronchus and underscores the spatial relationship of the segmental bronchi and the small caliber of the apical segmental bronchi (Apical). (C) Anterior and posterior bronchioles branch off a common bronchi. (D) The thick, mucus expectorated from the RA/P bronchus.
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Fig 2. High-resolution computed tomographic images of the thorax. (A) Two-dimensional coronal reformation of the lungs. Note hypolucent anterior segment of the right upper lobe that reflects reduced perfusion of this diseased segment. (B) Depicts the three-dimensional image of the central airways and right lung. Note direct origin of segmental bronchi from right mainstem bronchus (black arrows) with absence of a common right upper lobe bronchus. Also note bronchiectasis in the right upper lobe anterior segment (white arrow). (C) Sagittal reformatted computed tomographic image demonstrating saccular bronchiectasis (white arrows) within the anterior segment of the right upper lobe.
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At the time of surgery, confirmation of the bronchial anomaly was made by rigid bronchoscopy (Fig 1). The preoperative plan was to perform a right upper anterior segmentectomy in order to preserve as much lung parenchyma as possible. During exploration by muscle sparing thoracotomy, it was observed that the right lung did not have a minor fissure. Adhesions were present on the anterior and apical surfaces of the right upper lobe requiring adhesiolysis. The dissection of the hilum began by searching for the right middle lobe structures. Most unusual was the fact that the pulmonary veins draining the upper lobe traversed both anterior and posterior to the pulmonary artery and bronchus. The upper and posterior portions seemed to have veins draining posteriorly, and the anterior and inferior portions seemed to have veins draining anteriorly. Thus, these anomalous pulmonary veins completely surrounded the other hilar structures to the upper lobe. A pulmonary artery to the apical segment was identified, which bifurcated off of the right main pulmonary artery. In order to access the segmental bronchi and other pulmonary artery segmental branches, it was necessary to extensively mobilize the posterior branches of the upper lobe pulmonary veins until the main superior pulmonary vein. After dividing a pulmonary venous tributary, which was clearly draining only the anterior segment, further access was established to visualize some of the deeper hilar structures. At this point, a tiny segmental bronchus entering the anterior segment was identified. When followed back to its origin, another somewhat larger segmental bronchus going posterior to the pulmonary artery was also found at this location. The tiny bronchus going to the anterior segment was divided only after test clamping it and inflating the lungs, thus confirming that this was only serving the anterior segment. Of note, a large saccular bronchiectatic bronchiole was palpable within the anterior segment of the lobe, which was continuous with the small atretic bronchus. Division of the anterior segmental bronchus then exposed and facilitated division of a branch of the pulmonary artery, which was clearly the anterior segmental vessel. The remainder of the parenchymal division was performed with an endoscopic stapler. The specimen was removed and opened on the back table confirming a large bronchiectatic bronchiole. Placing a probe into the bronchus confirmed that it was contiguous with the tiny segmental bronchus that had been divided. The thoracotomy was closed with a single chest tube to suction drainage, and the child was extubated at the completion of the operation. Her postoperative course was uneventful with discharge on postoperative day 5.
Unfortunately, again, the patient had repeated episodes of productive cough shortly after surgery. These episodes responded to short courses of antibiotics, but still persisted for nearly 3 years of follow-up. Routine chest roentgenograms during these episodes failed to demonstrate pneumonic infiltrates, but a standard CT scan continued to show air trapping in the remaining right upper lobe. A gallium scan indicated no abnormal uptake in the right lung, but a ventilation and perfusion scan revealed decreased perfusion and delayed washout in the right upper lung regions. In an attempt to evaluate whether the febrile episodes reflect exacerbation of a chronic infection of the abnormal right sided airways, the patient had two flexible bronchoscopies within 6 months after the surgery, which revealed no pathogenic organisms and few inflammatory cells. It is difficult to ascertain whether the abnormal residual right upper lobe is responsible for the persistent symptomatology. The conundrum is further complicated by the coexistence of allergies and asthma confirmed by a bronchial biopsy from the right main bronchus that showed chronic bronchitis. Therefore, we are unable to answer with certainty whether a complete resection would have been more appropriate.
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Comment
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Although similar congenital abnormalities of the right upper lobe have been reported [3, 4], this particular anomaly involving both an absence of the normal right upper lobe bronchus as well as segmental right upper lobe bronchi arising from the trachea has not been previously described. However, the clinical presentation of this patient is common among patients with congenital airway abnormalities. The clinical presentation of bronchopulmonary malformations varies depending upon several features, including location, presence or absence of communication with the airways or gastrointestinal tract, and presence or absence of mass effect [5]. Some neonates are born with significant respiratory compromise requiring immediate mechanical assistance or resection, whereas others have a more protracted debilitating course. A high index of suspicion is required to make a diagnosis of a bronchopulmonary malformation. The anomaly described in this article could not be detected by routine radiographs and required the combination of a multidetector helical CT scan and bronchoscopy for diagnosis. Interestingly, a prior single detector helical CT scan was nondiagnostic due to respiratory motion. Notably the recent advent of the multidetector helical CT scanner results in significantly faster scanning with decreased respiratory motion, improved resolution, and enhanced quality of reconstructed images [6] as compared with the single detector helical scanner. By using a state-of-the-art multidetector CT scanner, the entire chest of this patient was scanned in only 4 seconds. Such fast speed virtually eliminates the problems of respiratory and cardiac motion.
Unlike a bronchogenic cyst or congenital lobar overinflation, this defect did not cause a discrete mass or mass effect, and therefore the defect was not detectable by routine radiographs [7]. The multidetector helical CT scan and bronchoscopy were able to detect the anomaly and provide a road map to allow a segmentectomy rather than a lobectomy. If the child had received intravenous contrast for the scan, it is likely that the aberrant vascular distribution to the upper lobe may have been identified preoperatively, potentially facilitating the surgical dissection.
In neonates with respiratory distress or children with recurrent pneumonias, a high index of suspicion must be maintained to exclude the presence of a bronchopulmonary anomaly. Although routine radiographs usually detect obvious lesions, such as aspirated foreign bodies, bronchogenic cysts, congenital cystic adenomatoid malformations, or sequestrations, more subtle lesions such as the one described in this article are frequently missed, resulting in delayed diagnosis and potential prolonged morbidity for the patient. A combination of bronchoscopic and CT scans may be useful to diagnose and plan for surgical intervention. The CT scan used to establish the diagnosis was especially helpful, because the three-dimensional images provided important information regarding the spatial relationships of the segmental bronchi. Three-dimensional CT reconstruction methods have been shown to provide relevant supplemental diagnostic information to conventional axial CT images in a majority of cases of complex tracheobronchial deformities [8]. In this particular case, the information provided by these images facilitated preoperative planning regarding surgical approach and extent of resection.
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References
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Abstract
Introduction
