(Chest. 2001;119:947-949.)
© 2001
American College of Chest Physicians
Lung Mass in a Smoker*
Baseem Daoud, MD;
Rogelio Moncada, MD and
Juzar Ali, MD, FCCP
*
From the Department of Medicine, Section of Pulmonary/Critical Care Medicine, and Department of Radiology, Louisiana State University Health Sciences Center, New Orleans, LA.
Correspondence to: Juzar Ali, MD, FCCP, Associate Professor of Medicine, Louisiana State University Health Sciences Center, 1901 Perdido St, Box P3–5, MEB Bldg, Suite 3205, New Orleans, LA 70112-1393; e-mail: jali{at}lsumc.edu
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Introduction
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A 39
-year-old man was seen in the
emergency department for vague abdominal pain. The workup at that
time was unrevealing, and the pain resolved with symptomatic
treatment. An abdominal radiograph series showed a nonspecific bowel
pattern and an incidental right lower lung zone calcified opacity. A
purified protein derivative tuberculin skin test was performed and
interpreted as positive with a 10-mm induration. He was referred to the
tuberculosis clinic for further evaluation. He denied any specific
respiratory symptoms. His medical history was noncontributory,
with a negative review of systems. He had a 10-pack-year history of
smoking, with no other substance abuse. The physical examination was
unremarkable.
A chest radiograph showed a right lower zone nodule. It also
showed a well-circumscribed semilunar opacity in the left perihilar
region (Fig 1
). A CT scan of the chest confirmed the presence of a calcified
granuloma in the right middle lobe. It also showed a 2 x 3 x 3-cm
soft tissue nodule in the anterior segment of the left upper lobe
associated with a bulla in that region. The nodule did not enhance with
contrast nor did it contain calcium or fat (Fig 2
).
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Figure 2.. CT scan of the chest showing a 2 x 3 x 3-cm
nonenhancing, noncalcified soft tissue nodule (gray arrow) in the
anterior segment of the left upper lobe associated with a bulla (black
arrows) in that region.
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Fiberoptic bronchoscopy did not reveal any endobronchial masses,
stenosis, or foreign bodies. Multiple endobronchial biopsies, washings,
and brushings showed chronic inflammatory changes with no evidence of
malignancy. Acid-fast bacilli and fungal smear results were negative.
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What is the diagnosis?
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Diagnosis: Congenital bronchial atresia
Bronchial atresia is the second most common congenital
tracheobronchial malformation after pulmonary
sequestration.1
It is characterized by the presence of a
short, localized area of stenosis of a single segmental or lobar
bronchus. Distal to the stenosis, the bronchi become filled with mucus
to form a bronchocele.
Bronchial atresia is seen most commonly in young adult male patients,
and 50% of these patients are asymptomatic. The abnormality is usually
discovered during a routine screening chest
radiograph.1
2
3
Symptomatic patients present with
recurrent pneumonia, dyspnea, cough, hemoptysis, or neonatal
respiratory distress.1
2
3
A localized area of reduced
breath sounds was the most common finding in most patients reported in
the literature,1
and wheezing is heard in patients with
history of asthma. The diagnosis is suspected by the radiographic
finding of a juxtahilar mass surrounded by regional
hypertranslucency.2
4
Additional radiographic features may
include mucus-filled bronchi (bronchocele), and branching opacities
radiating from the hilum.3
Air-fluid level within the
bronchocele may occasionally be seen. Air trapping around the affected
area that cannot be eliminated during expiration, probably due to a
check valve mechanism, results in an obstructive segmental or lobar
emphysema.1
2
3
A CT scan confirms the above findings and
is currently the most sensitive test available for demonstrating the
features of congenital bronchial atresia and to rule out
the presence of an obstructing endobronchial lesion.5
Spiral CT scan with multiplanar volumetric reconstruction is helpful in
distinguishing a mucocele from vascular malformations.5
Other imaging techniques, including bronchography and MRI, are either
difficult to interpret or unable to define the regional
hypertranslucency around the bronchocele that is well visualized by CT
scan.1
3
Arteriography is used to exclude the presence of
pulmonary sequestration if suspected. Ventilation lung scan reveal
delayed ventilation due to high resistance collateral pathway to
radioisotope entrance, and perfusion is decreased because of
hyperinflation-induced reduction in blood supply.1
Bronchoscopy, usually with normal findings, should be performed to
further exclude the presence of an obstructing endobronchial
lesion.2
3
Pathologic findings in patients who underwent resection for
"recurrent pneumonias" revealed that the left upper lobe was the
most common location. Grossly, the involved segment or lobe is markedly
emphysematous and free of anthracotic pigment because of the relative
lack of regional ventilation. Cystic dilatation of the atretic bronchus
is distinguished from bronchiectasis by the presence of normally
branching and distally extending bronchi. The involved parenchyma shows
alveolar hypoplasia, a probable consequence of decreased ventilation
and perfusion. These alveoli, however, remain open by collateral air
drift.1
Pathophysiologically, congenital bronchial atresia
is an example of collateral ventilation that occurs by one
of the following pathways: (1) the interalveolar pores of Kohn (air
drift); (2) the bronchoalveolar channels of Lambert, or (3) the
interbronchiolar channels.1
The last appears to be
the major route for collateral ventilation.1
An ischemic
etiology has been proposed to explain the mechanism of atresia
formation.6
Development of the bronchial buds occurs
between the 4th and 15th weeks of gestation. A vascular insult during
this period may cause interruption of the process, resulting in
fibrosis and atresia of the involved segment. The normal
appearance of the lung parenchyma distal to the atretic
segment is supportive of a late development of the atresia after
bronchial development is completed. The frequency of involvement is in
the following order: left upper lobe, 64%; left lower lobe, 14%; and
right lower and middle lobes in only 8%.3
The high
frequency of involvement of the left upper lobe supports the ischemic
theory, since the left upper lobe is the area of embryonic instability
that develops late in utero.1
3
6
Beside
congenital bronchial atresia, bronchoceles are seen in cases of
acquired bronchial obstruction secondary to allergic bronchopulmonary
aspergillosis, malignant tumors, and tuberculous bronchostenosis, and
can be confused with tuberculomas, hydatid cysts and solitary pulmonary
nodules. However, distal hyperinflation is seen only in bronchial
atresia, intralobar pulmonary sequestration, and bronchogenic
cysts.1
7
Radiography, CT, and bronchoscopy usually help
make the distinction among these differentials.
Asymptomatic patients require no treatment, provided that other
diagnoses are excluded by appropriate imaging techniques and
bronchoscopy. Surgical intervention is reserved for patients who
present with complications, such as recurrent pneumonia, or when there
is encroachment of normal pulmonary tissue.3
8
The
prognosis is usually excellent, and patients need only be observed for
complications. No specific therapy is required.
Our patient was referred to the tuberculosis clinic because of the
abnormal chest radiograph and positive purified protein
derivative skin test, but he was otherwise asymptomatic.
The diagnosis was made from the characteristic features on the chest
radiograph and CT scan. Bronchoscopy excluded an endobronchial lesion.
There was no evidence of active tuberculosis. He was evaluated for
tuberculosis chemoprophylaxis for latent tuberculosis, and will be
followed in the chest clinic for any future complications.
Received for publication March 7, 2000.
Accepted for publication April 3, 2000.
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References
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Jederlinic, PJ, Sicilian, L, Baigelman, W, et al (1986) Congenital bronchial atresia: a report of 4 cases and a review of the literature. Medicine 65,73-83[Medline]
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Ouzidane, L, Benjelloun, A, El Hajjam, M, et al (1999) Segmental bronchial atresia: a case report and a literature review Eur J Pediatr Surg 9,49-52
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Ward, S, Morcos, SK (1999) Congenital bronchial atresia: presentation of three cases and a pictorial review. Clin Radiol 54,144-148[CrossRef][ISI][Medline]
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Talner, LB, Gmelich, JT, Liebow, AA, et al (1970) The syndrome of bronchial mucocele and regional hyperinflation of the lung. AJR Am J Roentgenol 110,675-686[Abstract]
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Beigelman, C, Howarth, NR, Chartrand-Lefebvre, C, et al (1998) Congenital anomalies of tracheobronchial branching pattern: spiral CT aspects in adults. Eur Radiol 8,79-85[CrossRef][ISI][Medline]
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Waddell, JA, Simon, G, Reid, L (1965) Bronchial atresia of the upper lobe. Thorax 20,214-218
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Felson, B (1979) Mucoid impaction in segmental bronchial obstruction. Radiology 133,9-16[Abstract]
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Mori, M, Kidogawa, H, Moritaka, T, et al (1993) Bronchial atresia: report of a case and review of the literature. Surg Today 23,449-454[CrossRef][ISI][Medline]
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Introduction
What is the diagnosis?
