What are the abnormalities?
Section 1
Look at images 1 and 2.
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What are the abnormalities? | ||||||
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Note regions of bronchial wall thickening in the posterior lung. | ||||||
How do the number and size of the vessels and bronchi in the abnormally lucent lung (RUL(image 1) and lung bases (image 2)) compare with vessels in the more normal lung?
Section 2: Gross Appearance
A slice of dried lung with similar disease is shown below. Note the predominance of disease in the upper, rather than the lower, lung in this case (left). The image at the right shows the transition from marked (top) to milder (bottom) disease. The entire lobule is involved in both regions despite the difference in severity. At autopsy, lungs with this condition remain inflated and do not collapse when the chest is opened or even after the lungs are removed from the body. The cut surfaces are softer than normal to palpation.
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Section 3
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Histologic Features Here, bronchioles, alveoli, and pleura (upper left) are shown. The large airway has fewer alveolar wall attachments than normal. Its wall is thin. Alveolar areas show a diagnostic artifact--free floating alveolar walls (no attachments at either end). Fibrosis is minimal. Find 2 bronchioles. Find 4 free-floating alveolar walls. How would you describe the size of the alveoli? | ||||||
Differential diagnosis of abnormally lucent lung on HRCT: The findings are characteristic of panlobular emphysema. Patchy lucent regions of smaller size with decreased vasculature may be seen in regions of focal air-trapping (asthma, bronchiolitis obliterans, and bronchiectasis) or in vascular disease (chronic pulmonary embolism, plexogenic arteriopathy, and veno-occlusive disease).
Histologic differential diagnosis: Causes include cigarette smoking and alpha-1-antitrypsin deficiency. Intravenous drug use has been associated with emphysema.
Diagnosis: Panlobular emphysema in a patient with alpha-1-antitrypsin deficiency
Diagnostic features of panlobular emphysema on HRCT
See Case Study 25 for another example of emphysema.
a) Areas of abnormally lucent
lung (images 1 and 2)
b) Band-like linear opacities (image 2).
The abnormally lucent lung is most prominent at the lung bases and in the anterior RUL. The linear, band-like opacities and bronchial wall thickening in the lower lobes probably represent scar related to focal infection.
The vessels and bronchi in the abnormally lucent lung are smaller and fewer in number (more spread apart) than in the more normal lung.
Bronchiole. Note the very thin wall.
On average they are larger than normal and vary in size. Loss of alveolar walls causes a decrease in diffusing capacity and a loss of elastic recoil that causes small airways to collapse early on expiration and trap air. The trapped air compresses large airways to cause the patient's wheeze.
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