Bilateral micronodular pulmonary infiltrate: is it important to make a histological diagnosis?

Pulmonary alveolar microlithiasis is a rare disease characterized by the deposition of calcium phosphate within the alveoli. We report the case of a 20-year-old man with a 6-week history of cough and shortness of breath on exertion. The chest radiograph demonstrated a bilateral symmetrical micronodular pattern. High-resolution computed tomography revealed bilateral diffuse fine nodular shadowing involving the mid zones, with sparing of the apices. The patient underwent a transbronchial lung biopsy, which confirmed the diagnosis of pulmonary alveolar microlithiasis.