- Deposition of tiny stones mainly made of calcium phosphate in air spaces
- Mutations in SLC34A2 gene. This gene codes for sodium dependent phosphate transporter in type II alveolar cells
- Causes phosphate accumulation
- 30-50 years age
- Asymptomatic at presentation
Imaging
- Chest Xray
- Widespread discrete high density opacities (resembling sand grains)
- When profusely involving lungs, similar to a white out appearance
- Obscuration of heart borders and diaphragm
- Black sub pleural lung due to small cysts or paraseptal emphysema
- Thickening or beading of fissures
- Apical blebs
- Kerley B lines rarely
- CT
- Widespread ground-glass opacification
- Micro nodular pattern
- Predominantly lower zones and posteriorly
- Thickening of fissures and interlobular septa
- Crazy paving pattern
Read more
Ufuk, Furkan. “Pulmonary Alveolar Microlithiasis.” Radiology 298.3 (2021): 567-567.