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Computed Tomography Correlation of Airway Disease With Bronchoscopy: Part I—Nonneoplastic Large Airway Diseases
Computed Tomography Correlation of Airway Disease With Bronchoscopy: Part I—Nonneoplastic Large Airway Diseases Emmanuel C. Obusez, MD,a Lamia Jamjoom, MD,b Jacobo Kirsch, MD,c Thomas Gildea, MD,d and Tan-Lucien Mohammed, MD, FCCPe To illustrate and describe computed tomographic large airway pathology and correlate with fiberoptic bronchoscopy findings. Commonly encountered diseases of the large airway include tracheobronchial amyloidosis, tracheobronchopathia osteochondroplastica, tracheobronchomegaly, laryngotracheobronchial papillomatosis, relapsing polychondritis, Wegener granulomatosis, sarcoidosis, and tracheal stenosis. Computed tomography manifestations and bronchoscopic findings of these selected large airway diseases are discussed.
Education Goals Large airway diseases are uncommon and are classified as diffuse or focal. Focal airway involvement is neoplastic or infectious in etiology, whereas diffuse involvement includes nonneoplastic diseases of the trachea and bronchi. Computed tomography (CT) plays a major role in the characterization of diffuse abnormalities and is a feasible modality in the planning of therapeutic intervention. However, bronchoscopy with biopsy remains the gold standard for diagnosis of diffuse tracheobronchial abnormalities. In this article, correlation of the CT manifestations and the bronchoscopic findings of some nonneoplastic large airway diseases including tracheobronchial From the aImaging Institute, Cleveland Clinic, Cleveland, OH; bDepartment of Radiology, King Abdul Aziz University Hospital, Jeddah, Saudi Arabia; cDivision of Radiology, Cleveland Clinic Florida, Weston, FL; d Department of Pulmonary, Allergy and Critical Care, Cleveland Clinic, Cleveland, OH; and eDepartment of Radiology, Virginia Mason Medical Center, Seattle, WA. Reprint requests: Tan-Lucien H. Mohammed, MD, FCCP, Department of Radiology, Virginia Mason Medical Center, Seattle, WA. E-mail: [email protected]. Curr Probl Diagn Radiol 2014;43:268–277. & 2014 Mosby, Inc. All rights reserved. 0363-0188/$36.00 + 0 http://dx.doi.org/10.1067/j.cpradiol.2014.05.002
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amyloidosis, tracheobronchopathia osteochondroplastica, tracheobronchomegaly, laryngotracheobronchial papillomatosis, relapsing polychondritis, Wegener granulomatosis, sarcoidosis, and tracheal stenosis are reviewed.
Teaching Points and Pictorials Tracheobronchial Amyloidosis Primary pulmonary amyloidosis occurs either with diffuse parenchymal, nodular, or tracheobronchial involvement. Tracheobronchial amyloidosis is the most frequent subtype of pulmonary amyloidosis. CT findings commonly appear as multinodular eccentric protrusions into the tracheal lumen or diffuse circumferential submucosal wall thickening with luminal narrowing1 (Fig 1A-D). When present, calcification or ossification is concentric with involvement of the posterior tracheobronchial wall. This helps to differentiate from tracheobronchopathia osteochondroplastica or relapsing polychondritis, which have typical posterior wall sparing. Bronchoscopy findings may reveal evidence of submucosal infiltration, giving the mucosa an irregular, nodular appearance (Fig 1E). On rare occasions, a masslike process or amyloid pseudotumor may be present.2
Tracheal Stenosis Tracheal stenosis may occur as a complication of either endotracheal intubation or tracheostomy tube placement. Typically, mucosal necrosis with fibrosis and subsequent stenosis occur at the subglottic region, a common site of endotracheal tube-induced trauma, or at the stoma in cases of tracheostomy-induced trauma. On routine axial CT scan, the trachea may show a less-than-2.5-cm short concentric or eccentric segment narrowing of the lumen with a focal pinpoint airway3 (Fig 2A). Tracheal stenosis is further
Curr Probl Diagn Radiol, September/October 2014
FIG 1. Tracheobronchial amyloidosis. (A) Axial CT image of the trachea demonstrating eccentric nodular masses along the posterolateral wall (arrow). (B) Axial image from the same patient at the level of the carina and main stem bronchi demonstrating diffuse circumferential wall thickening with foci of calcifications and luminal narrowing (arrow). (C) Coronal reformatted image from the same patient demonstrating the diffuse circumferential wall thickening and luminal narrowing (arrow). (D) Sagittal reformatted image from the same patient showing the same findings (arrow). (E) Endobronchial amyloidosis with irregular nodularity of the submucosa, note the waxy yellow endobronchial submucosal lesions. (Color version of figure is available online.)
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FIG 2. Tracheal stenosis. (A) Axial CT scan of the trachea showing a short segment narrowing (450%) of the trachea at the level of the thoracic inlet with focal pinpoint airway just caudad at the level of the clavicular head (arrow). (B) Sagittal reformatted image of the trachea demonstrating the short segment narrowing (450%) of the trachea at the level of the thoracic inlet (arrow). (C) Bronchoscopy of an endotracheal tube-related tracheal stricture. Tracheal stenosis may also be tracheostomy induced. Note the complex spiral scaring of the mucosa. (Color version of figure is available online.)
appreciated with multiplanar reconstructions that demonstrate the severity and extent of the stenosis in relationship to the glottis (Fig 2B). Bronchoscopy findings may reveal a circumferential luminal narrowing less than 2 cm in length, a thin membrane that projects into the lumen, or a long segment of eccentric soft-tissue thickening4 (Fig 2C).
Sarcoidosis Sarcoidosis is a systemic inflammatory disease of unknown etiology characterized by noncaseating
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granulomas. Airway disease involves the upper trachea, with the distal and primary bronchi rarely affected. Hilar and mediastinal lymphadenopathy with perilymphatic pulmonary nodules are common radiographic findings. CT shows nodular stenosis or smooth, irregular concentric tracheobronchial wall thickening (Fig 3A-D). Extrinsic bronchial compression from lymphadenopathy is also seen.5 The described bronchoscopic manifestation is that of a raised “cobblestone” appearance of the mucosa. In addition, whitish granulomatous material may be seen in stenotic or strictured regions (Fig 3E and F).
Curr Probl Diagn Radiol, September/October 2014
FIG 3. Sarcoidosis. (A and B) Axial images from a HRCT showing concentric wall thickening and irregularity of the trachea and bilateral main stem bronchi (arrow). (C) Coronal CT image from the same patient demonstrating the concentric wall thickening of the trachea and main stem bronchi (arrow). (D) Sagittal reformatted image from the same patient demonstrating the concentric wall thickening of the trachea and main stem bronchi (arrow). (E and F) Endobronchial sarcoidosis characterized by cobble stoning (left) or airway strictures (right). HRCT, high-resolution CT. (Color version of figure is available online.)
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FIG 4. Wegener granulomatosis. (A) Axial CT image showing a nodule with slightly irregular margins circumscribing the anterior segmental bronchus of the left upper lobe bronchus and superior segmental bronchus of the lingula (arrow). (B) Axial image from a CT scan demonstrating polypoid densities in the airways representing sequelae of vasculitis. (C) Sagittal reformatted image from the same patient showing the nodular thickening circumscribing the bronchi (arrow). (D) Active Wegener granulomatosis showing mucosal infiltration. (Color version of figure is available online.)
Wegener Granulomatosis Wegener granulomatosis is a systemic necrotizing granulomatous vasculitis with a predilection for the upper airways. Subglottic tracheal involvement is most common. CT scan may show focal nodular or diffuse circumferential tracheobronchial wall thickening with luminal narrowing and calcification of the cartilaginous tracheal rings6 (Fig 4A-C). Bronchoscopic findings include inflammatory mucosal changes, ulcers, and subglottic stenosis commonly (Fig 4D). Yellow-green plaques usually correlate with
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active disease on diagnostic biopsy. Obstructive endobronchial pseudotumors of inflammatory granulomatous tissue have also been reported while cicatricial tracheal or bronchial stenosis is rare.7
Tracheobronchopathia Osteochondroplastica Tracheobronchopathia osteochondroplastica is an idiopathic and often asymptomatic benign disease of the trachea and major bronchi characterized by multiple submucosal osteocartilaginous nodules. These
Curr Probl Diagn Radiol, September/October 2014
FIG 5. Tracheobronchopathia osteochondroplastica. (A) Axial image from a nonenhanced CT scan of the chest showing deformity of the tracheal cartilage with some submucosal calcifications projecting into the lumen (arrow). No evidence of involvement of the posterior wall of the trachea. (B and C) Coronal and sagittal reformatted image from the same patient showing the submucosal calcifications projecting into the tracheal lumen (arrows). (D) Tracheopathia osteochondroplastic characterized by the nodules on the cartilages (black arrows) with sparing the posterior membranous airway (white arrow). (Color version of figure is available online.)
focal or diffuse nodules classically affect the lower two-thirds of the trachea and proximal portions of the main stem bronchi. CT findings demonstrate thickened tracheal cartilage with wavy, irregular mucosal calcification, with characteristic sparing of the noncartilaginous posterior wall, and long-segment nodular narrowing8 (Fig 5A-C). Typical bronchoscopic findings include numerous firm, yellow-white, osteocartilaginous nodules with anterolateral wall and main bronchi distribution patterned around the cartilaginous rings9 (Fig 5D).
Curr Probl Diagn Radiol, September/October 2014
Relapsing Polychondritis Relapsing polychondritis is an autoimmune connective tissue disease with diffuse or localized airway involvement. The larynx and upper trachea are affected most frequently, but disease involvement to the subsegmental airways may be seen. Classic characteristic lesions include thickening and calcification of the tracheal wall, with destruction and fibrosis of the cartilaginous rings and sparing of the posterior membrane of the trachea. CT imaging commonly reveals
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FIG 6. Relapsing polychondritis. (A and B) Axial image from a contrast-enhanced CT demonstrating diffuse central bronchial wall thickening (arrow). Also noted is focal stenosis at the origin of the superior segment of the left lower lobe bronchus (arrow). (C) Relapsing polychondritis. Note indistinct tracheal rings with narrow, collapsing trachea at the level of the carina, resembling an esophagus. (Color version of figure is available online.)
smooth diffuse wall thickening of the anterior and lateral tracheal walls with posterior membrane sparing (Fig 6A and B). Long, fixed airway narrowing and mural thickening with tracheobronchial strictures associated with air trapping, malacia, and airway collapse can be seen if an expiratory CT is performed.10 Typically, bronchoscopic findings demonstrate diffuse fixed airway narrowing with edematous, erythematous tracheobronchial walls and trancheobroncheomalacia with airway collapse11 (Fig 6C).
Laryngotracheobronchial Papillomatosis Laryngotracheobronchial papillomatosis is caused by human papilloma virus infection, commonly via
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vertical transmission during birth. It is characterized by benign lesions in the larynx, trachea, and bronchi, with limited lung involvement. Malignant transformation has been described. Central lesions resemble skin papillary lesions, with large masslike protrusions causing airway obstruction. Peripheral lesions are nodular, growing 5-50 mm with thick- and thin-wall cavitations.12 CT scan commonly reveals solitary or multiple, sessile or pedunculated, polypoid parenchymal nodules aggregating as intraluminal masses with pneumatoceles and thick-wall cavities (Fig 7A). On bronchoscopy, white polypoid “cauliflower” papillomas may be visualized in the larynx, trachea, or bronchi13 (Fig 7B and C).
Curr Probl Diagn Radiol, September/October 2014
Tracheobronchomegaly (Mounier-Kuhn Syndrome) Mounier-Kuhn syndrome is tracheobronchomegaly from a congenital deficiency in the internal elastic membrane of the trachea and central bronchi. Patients usually have marked dilatation of the trachea and main stem bronchi. Often, it is associated with recurrent lower respiratory tract infection and bronchiectasis. CT imaging demonstrates diffuse thinning of the
tracheobronchial walls, with greater than 3-cm dilation of the tracheal lumen (measured 2 cm above the aortic arch) or main stem bronchi. Diverticuli between the cartilaginous rings give the trachea and proximal bronchi an irregular or corrugated characteristic appearance14 (Fig 8A and B). Collapse of the trachea can be seen with forced expiration. Bronchoscopy findings show tracheal dilation, diverticuli on the tracheal wall, and enlargement of both main stem bronchi15 (Fig 8C and D).
FIG 7. Laryngotracheobronchial papillomatosis. (A) Axial thin-section CT image of the trachea showing a nodule on the nondependent anterior surface of the trachea (arrow). (B and C) Recurrent respiratory papillomatosis (HPV) can have several different appearances. The classic is the mulberry appearance (left) but mucosal infiltration (right) and transformation to squamous carcinoma can also occur. (Color version of figure is available online.)
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FIG 8. Tracheobronchomegaly (Mounier-Kuhn syndrome). (A and B) Axial CT images at the level of the trachea and main stem bronchi demonstrating marked irregularity and dilatation of the mucosal surface of both main stem bronchi and proximal bronchi bilaterally. (C) Coronal reformatted image from the same patient demonstrating the marked irregularity of the mucosal surface of the main stem bronchi (arrow). (D and E) Bronchoscopy findings with tracheal dilation and diverticula protruding between the tracheal rings. (Color version of figure is available online.)
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Curr Probl Diagn Radiol, September/October 2014
REFERENCES 1. Kim HY, Im JG, Song KS, et al. Localized amyloidosis of the respiratory system: CT features. J Comput Assist Tomogr 1999;23: 627-31. 2. Utz JP, Swensen SJ, Gertz MA. Pulmonary amyloidosis. The Mayo Clinic experience from 1980 to 1993. Ann Intern Med 1996;124:407-13. 3. Whyte RI, Quint LE, Kazerooni EA, et al. Helical computed tomography for the evaluation of tracheal stenosis. Ann Thorac Surg 1995;60:27-30 [discussion 30-1]. 4. Sarper A, Ayten A, Eser I, et al. Tracheal stenosis after tracheostomy or intubation: Review with special regard to cause and management. Tex Heart Inst J 2005;32: 154-8. 5. Muller NL, Kullnig P, Miller RR. The CT findings of pulmonary sarcoidosis: Analysis of 25 patients. Am J Roentgenol 1989;152:1179-82. 6. Lee KS, Kim TS, Fujimoto K, et al. Thoracic manifestation of Wegener's granulomatosis: CT findings in 30 patients. Eur Radiol 2003;13:43-51. 7. Daum TE, Specks U, Colby TV, et al. Tracheobronchial involvement in Wegener's granulomatosis. Am J Respir Crit Care Med 1995;151:522-6.
Curr Probl Diagn Radiol, September/October 2014
8. Restrepo S, Pandit M, Villamil MA, et al. Tracheobronchopathia osteochondroplastica: Helical CT findings in 4 cases. J Thorac Imaging 2004;19:112-6. 9. Hodges MK, Israel E. Tracheobronchopathia osteochondroplastica presenting as right middle lobe collapse. Diagnosis by bronchoscopy and computerized tomography. Chest 1988;94: 842-4. 10. Lee KS, Ernst A, Trentham DE, et al. Relapsing polychondritis: Prevalence of expiratory CT airway abnormalities. Radiology 2006;240:565-73. 11. Dolan DL, Lemmon GB Jr, Teitelbaum SL. Relapsing polychondritis. Analytical literature review and studies on pathogenesis. Am J Med 1966;41:285-99. 12. Gruden JF, Webb WR, Sides DM. Adult-onset disseminated tracheobronchial papillomatosis: CT features. J Comput Assist Tomogr 1994;18:640-2. 13. Colt HG, Murgu SD, Jung B, et al. Multimodality bronchoscopic imaging of recurrent respiratory papillomatosis. Laryngoscope 2010;120:468-72. 14. Shin MS, Jackson RM, Ho KJ. Tracheobronchomegaly (Mounier-Kuhn syndrome): CT diagnosis. Am J Roentgenol 1988;150:777-9. 15. Celik B, Bilgin S, Yuksel C. Mounier-Kuhn syndrome: A rare cause of bronchial dilation. Tex Heart Inst J 2011;38:194-6.
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Education Goals Large airway diseases are uncommon and are classified as diffuse or focal. Focal airway involvement is neoplastic or infectious in etiology, whereas diffuse involvement includes nonneoplastic diseases of the trachea and bronchi. Computed tomography (CT) plays a major role in the characterization of diffuse abnormalities and is a feasible modality in the planning of therapeutic intervention. However, bronchoscopy with biopsy remains the gold standard for diagnosis of diffuse tracheobronchial abnormalities. In this article, correlation of the CT manifestations and the bronchoscopic findings of some nonneoplastic large airway diseases including tracheobronchial From the aImaging Institute, Cleveland Clinic, Cleveland, OH; bDepartment of Radiology, King Abdul Aziz University Hospital, Jeddah, Saudi Arabia; cDivision of Radiology, Cleveland Clinic Florida, Weston, FL; d Department of Pulmonary, Allergy and Critical Care, Cleveland Clinic, Cleveland, OH; and eDepartment of Radiology, Virginia Mason Medical Center, Seattle, WA. Reprint requests: Tan-Lucien H. Mohammed, MD, FCCP, Department of Radiology, Virginia Mason Medical Center, Seattle, WA. E-mail: [email protected]. Curr Probl Diagn Radiol 2014;43:268–277. & 2014 Mosby, Inc. All rights reserved. 0363-0188/$36.00 + 0 http://dx.doi.org/10.1067/j.cpradiol.2014.05.002
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amyloidosis, tracheobronchopathia osteochondroplastica, tracheobronchomegaly, laryngotracheobronchial papillomatosis, relapsing polychondritis, Wegener granulomatosis, sarcoidosis, and tracheal stenosis are reviewed.
Teaching Points and Pictorials Tracheobronchial Amyloidosis Primary pulmonary amyloidosis occurs either with diffuse parenchymal, nodular, or tracheobronchial involvement. Tracheobronchial amyloidosis is the most frequent subtype of pulmonary amyloidosis. CT findings commonly appear as multinodular eccentric protrusions into the tracheal lumen or diffuse circumferential submucosal wall thickening with luminal narrowing1 (Fig 1A-D). When present, calcification or ossification is concentric with involvement of the posterior tracheobronchial wall. This helps to differentiate from tracheobronchopathia osteochondroplastica or relapsing polychondritis, which have typical posterior wall sparing. Bronchoscopy findings may reveal evidence of submucosal infiltration, giving the mucosa an irregular, nodular appearance (Fig 1E). On rare occasions, a masslike process or amyloid pseudotumor may be present.2
Tracheal Stenosis Tracheal stenosis may occur as a complication of either endotracheal intubation or tracheostomy tube placement. Typically, mucosal necrosis with fibrosis and subsequent stenosis occur at the subglottic region, a common site of endotracheal tube-induced trauma, or at the stoma in cases of tracheostomy-induced trauma. On routine axial CT scan, the trachea may show a less-than-2.5-cm short concentric or eccentric segment narrowing of the lumen with a focal pinpoint airway3 (Fig 2A). Tracheal stenosis is further
Curr Probl Diagn Radiol, September/October 2014
FIG 1. Tracheobronchial amyloidosis. (A) Axial CT image of the trachea demonstrating eccentric nodular masses along the posterolateral wall (arrow). (B) Axial image from the same patient at the level of the carina and main stem bronchi demonstrating diffuse circumferential wall thickening with foci of calcifications and luminal narrowing (arrow). (C) Coronal reformatted image from the same patient demonstrating the diffuse circumferential wall thickening and luminal narrowing (arrow). (D) Sagittal reformatted image from the same patient showing the same findings (arrow). (E) Endobronchial amyloidosis with irregular nodularity of the submucosa, note the waxy yellow endobronchial submucosal lesions. (Color version of figure is available online.)
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FIG 2. Tracheal stenosis. (A) Axial CT scan of the trachea showing a short segment narrowing (450%) of the trachea at the level of the thoracic inlet with focal pinpoint airway just caudad at the level of the clavicular head (arrow). (B) Sagittal reformatted image of the trachea demonstrating the short segment narrowing (450%) of the trachea at the level of the thoracic inlet (arrow). (C) Bronchoscopy of an endotracheal tube-related tracheal stricture. Tracheal stenosis may also be tracheostomy induced. Note the complex spiral scaring of the mucosa. (Color version of figure is available online.)
appreciated with multiplanar reconstructions that demonstrate the severity and extent of the stenosis in relationship to the glottis (Fig 2B). Bronchoscopy findings may reveal a circumferential luminal narrowing less than 2 cm in length, a thin membrane that projects into the lumen, or a long segment of eccentric soft-tissue thickening4 (Fig 2C).
Sarcoidosis Sarcoidosis is a systemic inflammatory disease of unknown etiology characterized by noncaseating
270
granulomas. Airway disease involves the upper trachea, with the distal and primary bronchi rarely affected. Hilar and mediastinal lymphadenopathy with perilymphatic pulmonary nodules are common radiographic findings. CT shows nodular stenosis or smooth, irregular concentric tracheobronchial wall thickening (Fig 3A-D). Extrinsic bronchial compression from lymphadenopathy is also seen.5 The described bronchoscopic manifestation is that of a raised “cobblestone” appearance of the mucosa. In addition, whitish granulomatous material may be seen in stenotic or strictured regions (Fig 3E and F).
Curr Probl Diagn Radiol, September/October 2014
FIG 3. Sarcoidosis. (A and B) Axial images from a HRCT showing concentric wall thickening and irregularity of the trachea and bilateral main stem bronchi (arrow). (C) Coronal CT image from the same patient demonstrating the concentric wall thickening of the trachea and main stem bronchi (arrow). (D) Sagittal reformatted image from the same patient demonstrating the concentric wall thickening of the trachea and main stem bronchi (arrow). (E and F) Endobronchial sarcoidosis characterized by cobble stoning (left) or airway strictures (right). HRCT, high-resolution CT. (Color version of figure is available online.)
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FIG 4. Wegener granulomatosis. (A) Axial CT image showing a nodule with slightly irregular margins circumscribing the anterior segmental bronchus of the left upper lobe bronchus and superior segmental bronchus of the lingula (arrow). (B) Axial image from a CT scan demonstrating polypoid densities in the airways representing sequelae of vasculitis. (C) Sagittal reformatted image from the same patient showing the nodular thickening circumscribing the bronchi (arrow). (D) Active Wegener granulomatosis showing mucosal infiltration. (Color version of figure is available online.)
Wegener Granulomatosis Wegener granulomatosis is a systemic necrotizing granulomatous vasculitis with a predilection for the upper airways. Subglottic tracheal involvement is most common. CT scan may show focal nodular or diffuse circumferential tracheobronchial wall thickening with luminal narrowing and calcification of the cartilaginous tracheal rings6 (Fig 4A-C). Bronchoscopic findings include inflammatory mucosal changes, ulcers, and subglottic stenosis commonly (Fig 4D). Yellow-green plaques usually correlate with
272
active disease on diagnostic biopsy. Obstructive endobronchial pseudotumors of inflammatory granulomatous tissue have also been reported while cicatricial tracheal or bronchial stenosis is rare.7
Tracheobronchopathia Osteochondroplastica Tracheobronchopathia osteochondroplastica is an idiopathic and often asymptomatic benign disease of the trachea and major bronchi characterized by multiple submucosal osteocartilaginous nodules. These
Curr Probl Diagn Radiol, September/October 2014
FIG 5. Tracheobronchopathia osteochondroplastica. (A) Axial image from a nonenhanced CT scan of the chest showing deformity of the tracheal cartilage with some submucosal calcifications projecting into the lumen (arrow). No evidence of involvement of the posterior wall of the trachea. (B and C) Coronal and sagittal reformatted image from the same patient showing the submucosal calcifications projecting into the tracheal lumen (arrows). (D) Tracheopathia osteochondroplastic characterized by the nodules on the cartilages (black arrows) with sparing the posterior membranous airway (white arrow). (Color version of figure is available online.)
focal or diffuse nodules classically affect the lower two-thirds of the trachea and proximal portions of the main stem bronchi. CT findings demonstrate thickened tracheal cartilage with wavy, irregular mucosal calcification, with characteristic sparing of the noncartilaginous posterior wall, and long-segment nodular narrowing8 (Fig 5A-C). Typical bronchoscopic findings include numerous firm, yellow-white, osteocartilaginous nodules with anterolateral wall and main bronchi distribution patterned around the cartilaginous rings9 (Fig 5D).
Curr Probl Diagn Radiol, September/October 2014
Relapsing Polychondritis Relapsing polychondritis is an autoimmune connective tissue disease with diffuse or localized airway involvement. The larynx and upper trachea are affected most frequently, but disease involvement to the subsegmental airways may be seen. Classic characteristic lesions include thickening and calcification of the tracheal wall, with destruction and fibrosis of the cartilaginous rings and sparing of the posterior membrane of the trachea. CT imaging commonly reveals
273
FIG 6. Relapsing polychondritis. (A and B) Axial image from a contrast-enhanced CT demonstrating diffuse central bronchial wall thickening (arrow). Also noted is focal stenosis at the origin of the superior segment of the left lower lobe bronchus (arrow). (C) Relapsing polychondritis. Note indistinct tracheal rings with narrow, collapsing trachea at the level of the carina, resembling an esophagus. (Color version of figure is available online.)
smooth diffuse wall thickening of the anterior and lateral tracheal walls with posterior membrane sparing (Fig 6A and B). Long, fixed airway narrowing and mural thickening with tracheobronchial strictures associated with air trapping, malacia, and airway collapse can be seen if an expiratory CT is performed.10 Typically, bronchoscopic findings demonstrate diffuse fixed airway narrowing with edematous, erythematous tracheobronchial walls and trancheobroncheomalacia with airway collapse11 (Fig 6C).
Laryngotracheobronchial Papillomatosis Laryngotracheobronchial papillomatosis is caused by human papilloma virus infection, commonly via
274
vertical transmission during birth. It is characterized by benign lesions in the larynx, trachea, and bronchi, with limited lung involvement. Malignant transformation has been described. Central lesions resemble skin papillary lesions, with large masslike protrusions causing airway obstruction. Peripheral lesions are nodular, growing 5-50 mm with thick- and thin-wall cavitations.12 CT scan commonly reveals solitary or multiple, sessile or pedunculated, polypoid parenchymal nodules aggregating as intraluminal masses with pneumatoceles and thick-wall cavities (Fig 7A). On bronchoscopy, white polypoid “cauliflower” papillomas may be visualized in the larynx, trachea, or bronchi13 (Fig 7B and C).
Curr Probl Diagn Radiol, September/October 2014
Tracheobronchomegaly (Mounier-Kuhn Syndrome) Mounier-Kuhn syndrome is tracheobronchomegaly from a congenital deficiency in the internal elastic membrane of the trachea and central bronchi. Patients usually have marked dilatation of the trachea and main stem bronchi. Often, it is associated with recurrent lower respiratory tract infection and bronchiectasis. CT imaging demonstrates diffuse thinning of the
tracheobronchial walls, with greater than 3-cm dilation of the tracheal lumen (measured 2 cm above the aortic arch) or main stem bronchi. Diverticuli between the cartilaginous rings give the trachea and proximal bronchi an irregular or corrugated characteristic appearance14 (Fig 8A and B). Collapse of the trachea can be seen with forced expiration. Bronchoscopy findings show tracheal dilation, diverticuli on the tracheal wall, and enlargement of both main stem bronchi15 (Fig 8C and D).
FIG 7. Laryngotracheobronchial papillomatosis. (A) Axial thin-section CT image of the trachea showing a nodule on the nondependent anterior surface of the trachea (arrow). (B and C) Recurrent respiratory papillomatosis (HPV) can have several different appearances. The classic is the mulberry appearance (left) but mucosal infiltration (right) and transformation to squamous carcinoma can also occur. (Color version of figure is available online.)
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FIG 8. Tracheobronchomegaly (Mounier-Kuhn syndrome). (A and B) Axial CT images at the level of the trachea and main stem bronchi demonstrating marked irregularity and dilatation of the mucosal surface of both main stem bronchi and proximal bronchi bilaterally. (C) Coronal reformatted image from the same patient demonstrating the marked irregularity of the mucosal surface of the main stem bronchi (arrow). (D and E) Bronchoscopy findings with tracheal dilation and diverticula protruding between the tracheal rings. (Color version of figure is available online.)
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REFERENCES 1. Kim HY, Im JG, Song KS, et al. Localized amyloidosis of the respiratory system: CT features. J Comput Assist Tomogr 1999;23: 627-31. 2. Utz JP, Swensen SJ, Gertz MA. Pulmonary amyloidosis. The Mayo Clinic experience from 1980 to 1993. Ann Intern Med 1996;124:407-13. 3. Whyte RI, Quint LE, Kazerooni EA, et al. Helical computed tomography for the evaluation of tracheal stenosis. Ann Thorac Surg 1995;60:27-30 [discussion 30-1]. 4. Sarper A, Ayten A, Eser I, et al. Tracheal stenosis after tracheostomy or intubation: Review with special regard to cause and management. Tex Heart Inst J 2005;32: 154-8. 5. Muller NL, Kullnig P, Miller RR. The CT findings of pulmonary sarcoidosis: Analysis of 25 patients. Am J Roentgenol 1989;152:1179-82. 6. Lee KS, Kim TS, Fujimoto K, et al. Thoracic manifestation of Wegener's granulomatosis: CT findings in 30 patients. Eur Radiol 2003;13:43-51. 7. Daum TE, Specks U, Colby TV, et al. Tracheobronchial involvement in Wegener's granulomatosis. Am J Respir Crit Care Med 1995;151:522-6.
Curr Probl Diagn Radiol, September/October 2014
8. Restrepo S, Pandit M, Villamil MA, et al. Tracheobronchopathia osteochondroplastica: Helical CT findings in 4 cases. J Thorac Imaging 2004;19:112-6. 9. Hodges MK, Israel E. Tracheobronchopathia osteochondroplastica presenting as right middle lobe collapse. Diagnosis by bronchoscopy and computerized tomography. Chest 1988;94: 842-4. 10. Lee KS, Ernst A, Trentham DE, et al. Relapsing polychondritis: Prevalence of expiratory CT airway abnormalities. Radiology 2006;240:565-73. 11. Dolan DL, Lemmon GB Jr, Teitelbaum SL. Relapsing polychondritis. Analytical literature review and studies on pathogenesis. Am J Med 1966;41:285-99. 12. Gruden JF, Webb WR, Sides DM. Adult-onset disseminated tracheobronchial papillomatosis: CT features. J Comput Assist Tomogr 1994;18:640-2. 13. Colt HG, Murgu SD, Jung B, et al. Multimodality bronchoscopic imaging of recurrent respiratory papillomatosis. Laryngoscope 2010;120:468-72. 14. Shin MS, Jackson RM, Ho KJ. Tracheobronchomegaly (Mounier-Kuhn syndrome): CT diagnosis. Am J Roentgenol 1988;150:777-9. 15. Celik B, Bilgin S, Yuksel C. Mounier-Kuhn syndrome: A rare cause of bronchial dilation. Tex Heart Inst J 2011;38:194-6.
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