Pulmonary alveolar microlithiasis (PAM) is an uncommon chronic disease characterized by calcifications within the alveoli and a paucity of symptoms in contrast to the imaging findings. 

Pulmonary function tests in this patient showed a restrictive pattern. 

The chest radiograph demonstrated a bilateral symmetric micronodular pattern (not shown). 

High resolution CT scan revealed diffuse ground-glass attenuation with superimposed septal thickening (crazy-paving pattern). 

The patient underwent a lung biopsy, which confirmed the diagnosis of PAM.

PAM needs to be considered in the differential diagnosis of lung lesions that present with crazy-paving pattern on the high resolution CT.