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Chapter 23. Pathology of Restrictive Lung Diseases

The photograph of lung below (H&E) was obtained from a 60-year-old man with a 7-day history of fever, leukocytosis, systemic hypotension, and evolving multisystem organ failure. With the structure indicated by the arrow, which is the best diagnosis?

image

a. Diffuse alveolar damage

b. Hyaline membrane disease

c. Desquamative interstitial pneumonitis

d. Pulmonary alveolar proteinosis

e. Pneumocystis jiroveci infection

The most correct answer is a, diffuse alveolar damage.

The arrow is pointing to a hyaline membrane, which could be seen in diffuse alveolar damage (answer a) or hyaline membrane disease (answer b). Since hyaline membrane disease is a disease of neonates, the patient's age eliminates answer b; furthermore, the lung tissue in the image appears more mature than would be expected in a neonate. Desquamative interstitial pneumonitis (answer c) is characterized by aggregates of pigmented macrophages rather than the hyaline material shown. In pulmonary alveolar proteinosis (answer d), the intra-alveolar material is more granular than a hyaline membrane and typically fills the alveoli. Pneumocystis jiroveci infection is characterized by a foamy intra-alveolar exudate rather than the hyaline membrane shown here.

A 33-year-old woman has increasing dyspnea with cough for 10 days. Over the past 48 hours, her cough produced chunks of gelatinous sputum. Physical exam reveals no fever but extensive dullness to percussion over all lung fields. Chest x-ray shows diffuse opacification bilaterally. Biopsy yields the microscopic features shown at upper right (H&E stain); with electron microscopy there are many lamellar bodies. Antibodies directed against which of the following is most likely the cause of her illness?

image

a. Surfactant protein B

b. GM-CSF

c. Pneumocyte epithelial factor 2

d. Surfactant protein C

e. α3 chain of collagen IV

The most correct answer is b, GM-CSF.

The patient has pulmonary alveolar proteinosis (PAP), which, in the adult, is frequently caused by autoantibodies directed at GM-CSF. Mutations in surfactant protein B can underlie PAP in the neonate. Autoantibodies directed at the α3 chain of collagen IV are the cause of Goodpasture's syndrome. The name pneumocyte epithelial factor 2 has not been assigned to any known molecule.

A 60-year-old man shows fine nodularity in the upper lung fields of a chest x-ray. From ages 20-50, he was a ...

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