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Partial Duplication of the Trachea in an Adult: An Accidental Finding on Bronchoscopy

Choudhury, Sushmita MBBS; Patel, Anand K. MD

Journal of Bronchology & Interventional Pulmonology: October 2010 - Volume 17 - Issue 4 - p 365-366
doi: 10.1097/LBR.0b013e3181f55a47
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Partial duplication of the trachea is a very rare congenital tracheal anomaly that is detected during infancy. To our knowledge, there are only 3 reported cases of partial duplication of the trachea in the literature, which were all detected during infancy. We are reporting the first case of partial duplication of the trachea in an adult, which was detected accidentally during routine diagnostic bronchoscopy. Partial duplication of the trachea can easily be misdiagnosed as an accessory bronchus or congenital tracheal diverticulum, if it is not carefully evaluated. It is possible that similar cases in the past may have been misdiagnosed as tracheal bronchus or congenital tracheal diverticulum on bronchoscopy.

Department of Pulmonary Medicine, S. B. K. S. Medical Institute and Research Centre, Sumandeep Vidhyapeeth, Piparia, Vadodara, Gujarat, India

Financial support: none.

Reprints: Anand K. Patel, MD, A/15, Krishnadeep Society, B/h Saurabh Park, Near Samta, Subhanpura, Vadodara–390021, Gujarat, India (e-mail: dranandkpatel@gmail.com).

Received for publication June 17, 2010; accepted August 2, 2010

There is no conflict of interest.

Tracheal duplication is a rare congenital anomaly. Other congenital tracheal anomalies include tracheal web, congenital stenosis, cartilage anomalies, tracheal diverticulum, and anomalous bronchi that are distinct from tracheal duplication. To our knowledge, there are only 3 reported cases of partial duplication of the trachea. All the reported cases were detected during infancy. Haben et al1 reported a case of partial distal tracheal duplication that was diagnosed during a postmortem examination. Sen et al2 reported a case of complete tracheal duplication that was diagnosed on chest computed tomography (CT). Musturay et al3 reported a case of partial duplication of the mid–trachea, which was diagnosed on chest CT. To our knowledge, partial duplication of the trachea in adults has not been reported in the literature. We are reporting the first case of partial duplication of the trachea in an adult, which was detected accidentally during routine diagnostic bronchoscopy.

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CASE REPORT

A 50-year-old male patient presented with complaints of cough, chest pain, and change of voice for 25 days. He was a chronic smoker and had a history of pulmonary tuberculosis 6 years earlier. His chest radiograph showed left, middle zone homogenous opacity with raised left dome of the diaphragm. CT scan of the chest was suggestive of left hilar and parahilar lung mass with mediastinal lymphadenopathy. Flexible bronchoscopy was performed to obtain endobronchial biopsy and bronchial washings for histopathologic and cytologic examination, respectively. During the procedure, duplication of the distal trachea arising from the right posterolateral wall was detected, which was partial in nature (Fig. 1). There was no other endobronchial anomaly. To confirm our findings, a CT scan of the limited portion of the chest was performed wherein partial duplication of the trachea was evident (Fig. 2).

FIGURE 1.

FIGURE 1.

FIGURE 2.

FIGURE 2.

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DISCUSSION

Duplication of the trachea is rare, and to our knowledge, only 3 cases have been reported in the literature.1–3 One patient had partial duplication in the lower aspect of the trachea, which was seen as a partial union of the tracheal rings on postmortem analysis.1 The infant died shortly after birth from coexisting unilateral lung hypoplasia. The second patient had complete tracheal duplication extending from the thoracic inlet to the carina, which was diagnosed on nonhelical CT. Virtual bronchoscopic images were not obtained, and the duplicated trachea was shown only on 1 image in the case report.2 Before the CT procedure, the patient underwent fiberoptic laryngoscopy. The trachea could not be visualized because the laryngoscope could not pass beyond the larynx. The parents of the patient refused further treatment, and the severity of patient's stridor decreased significantly during the 1-year follow-up. The third patient had partial duplication of the mid-trachea. The 2-month-old boy was presented with stridor and a chest CT showed partial duplication of the mid-trachea.3 The embryologic basis of this anomaly may be similar to that of anomalous bronchi. Three major hypotheses have been formulated to explain anomalous bronchi: the reduction, migration, and selection theories.4 To our knowledge, duplication of the trachea has not been described in adults. All the reported cases were detected during infancy. This is the first case of partial duplication of the trachea detected in an adult. Partial duplication of the trachea can be easily misdiagnosed as an accessory bronchus or cardiac bronchus if it is not carefully evaluated during bronchoscopy. The endoluminal view is similar to that of the tracheal bronchus, and the distal part of the partially duplicated trachea is difficult to visualize on bronchoscopy, as noted in the 2 reported cases. Therefore, it is possible that similar cases in the past may have been misdiagnosed as tracheal bronchus on bronchoscopy.

Another differential diagnosis of tracheal duplication is tracheal diverticulum particularly of congenital type. Two types of tracheal diverticulum have been reported, congenital and acquired. Congenital diverticula are small and narrow-mouthed. Some occur in isolation and some are associated with other congenital anomalies of the tracheobronchial tree. The wall of a congenital diverticulum is similar to the wall of the trachea, containing smooth muscle fibers, cartilage, and respiratory epithelium. These pouches are believed to represent a vestigial supernumerary lung or an aborted, abnormally high division of the primary lung bud. They commonly arise on the right side of the trachea, approximately 4 to 5 cm below the true vocal folds or a few centimeters above the tracheal carina. Acquired diverticula are usually associated with chronic bronchopulmonary disease. They occur as a result of a herniation of the mucosa at a weak point in the tracheal wall secondary to increased intraluminal pressure caused by chronic cough. Mucosal herniations can occur anywhere in the tracheal wall, but most usually appear laterally between the cartilaginous rings or posterolaterally through the trachealis muscle. These pouches are typically wide-mouthed and larger than the congenital type. The wall of an acquired diverticulum is devoid of mucous glands, smooth muscles, and cartilage; it is lined with respiratory epithelium only.5–7

However, although there is no clear distinction between tracheal diverticulum and tracheal duplication in the literature, we still believe that our case is of tracheal duplication, as the defect had a wide opening that is unlikely in the case of congenital tracheal diverticulum, and the wall of the defect was similar to the wall of the trachea, which is unlikely in the case of acquired tracheal diverticulum.

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REFERENCES

1. Haben CM, Nguyen VH, Russell L, et al. Incomplete tracheal duplication associated with severe unilateral lung hypoplasia. J Laryngol Otol. 2003;117:215–218.
2. Sen MK, Mehta C, Chakrabarti S, et al. Tracheal duplication as a cause of congenital stridor. Indian J Chest Dis Allied Sci. 1999;41:159–162.
3. Musturay K, Mithat H, Saniye E. Partial tracheal duplication: MDCT bronchoscopic diagnosis. Am J Roentgenol. 2004;183:290–292.
4. Ghaye B, Szapiro D, Fanchamps J, et al. Congenital bronchial abnormalities revisited. Radiographics. 2001;21:105–119.
5. Sharma BG. Tracheal diverticulum: a report of 4 cases. Ear Nose Throat J. 2009;88:E11.
6. Goo JM, Im JG, Ahn JM, et al. Right para-tracheal air cysts in the thoracic inlet: clinical and radiologic significance. AJR. 1999;173:65–70.
7. Kokkonouzis I, Haramis D, Kornezos I, et al. Tracheal diverticulum in an asymptomatic male: a case report. Cases J. 2008;1:181.
Keywords:

partial duplication; trachea; bronchoscopy

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