The article provides up-to-date information on epidemiology, etiology, genetics, pathogenesis, pathomorphology, clinical manifestation, X-ray and computed tomography (CT) semiotics, features in childhood, treatment of a rare genetic interstitial lung disease – pulmonary alveolar microlithiasis (PAM). A clinical observation of a child with PAM manifestation, confirmed by lung biopsy in infancy, is presented. The results of X-ray and CT of the patient's chest organs are presented, the unique features of the course of the disease are listed.