• Accumulation of abundant protein rich and lipid rich material resembling surfactant in alveoli
  
• Radiographically, bilateral symmetric central airspace opacities or vague hazy opacities, perihilar and in lower lungs
  
• HRCT shows a “crazy-paving” appearance
  
• A third of patients are asymptomatic
  
• Occurs with massive silica dust exposure
  
• Associated with infections such as Nocardia
  
• Diagnosed and treated with BAL and irrigation
  
• Good prognosis

Chest radiograph

• Ill-defined nodular, or diffuse airspace opacification or vague ill-defined opacities
  
• Central perihilar batwing pattern
  
• Mixed interstitial and airspace opacities, less common
  

CT/HRCT

• HRCT shows geographic regions of airspace or ground glass opacities and linear interstitial opacities, giving a “crazy-paving” pattern.”
  
• Distribution of disease is random.

• Pulmonary edema
  
• Pneumonia
  
• Hemorrhage
  
• Bronchioloalveolar cell carcinoma
• Differentiation
• No cardiomegaly, pulmonary venous hypertension or effusions
  
• Pneumonia and hemorrhage can be excluded by clinical presentation and bronchoscopy
  
• Crazy-paving can also be seen in bronchioloalveolaar carcinoma, lipoid pneumonia, hemorrhage, pulmonary edema and bacterial pneumonia

• Accumulation of abundant protein rich and lipid rich material resembling surfactant
  
• Alveoli are filled with fine granular material that stains pink with PAS stain
  
• Abnormality of surfactant production, metabolism or clearance by type II alveolar cells and macrophages
  
• Often superinfected with infections with Nocardia, Aspergillus, Cryptococcus and other organisms.
  

• Uncommon
  
• Adults 20 to 50 years olds
  
• >2:1 male predominance
  
• Can occur in very young children
  
• Can occur with exposure to high concentrations of silicon dioxide dust or titanium
  
• Can occur in immuno-compromised children, or adults with lymphoma, leukemia, AIDS, or autoimmune disease
  
• Chest radiograph is abnormal out of proportion to patient’s symptoms
  
• 33% are asymptomatic, most common symptoms are dyspnea and cough
  
• Clubbing of fingers and toes
  
• Diagnosis with BAL or transbronchial biopsy
  
• Treatment, therapeutic BAL with whole lung irrigation, usually one to two times. Few patients require annual or biannual therapeutic BALs.
  
• Prognosis is good.
  
• Death from pulmonary fibrosis is rare.

Murch CR , Carr DH. Computed tomography appearances of pulmonary alveolar proteinosis Clin Radiol 40:240-243, 1989
Gale ME, Karlinsky JB , Robins AG. Bronchopulmonary lavage in pulmonary alveolar proteinosis: chest radiograph observations AJR Am J Roentgenol 146:981-985, 1986
Prakash UB, Barham SS, Carpenter HA, et al. Pulmonary alveolar phospholipoproteinosis: experience with 34 cases and a review Mayo Clin Proc 62:499-518, 1987