Pulmonary alveolar microlithiasis: A case report and review of the literature.

Pulmonary alveolar microlithiasis (PAM) is a rare autosomal recessive disease characterized by the formation of calcium phosphate microliths in the alveoli. Mutations in the gene encoding the solute carrier family 34 member 2 gene are considered to be involved in the pathogenesis of PAM. Although PAM can develop in children, the majority of patients with PAM are diagnosed in adulthood due to the slow progressive nature of the disease within the lungs. In childhood, the majority of patients with PAM are asymptomatic and changes in the lung parenchyma are usually identified incidentally. Symptoms of PAM typically appear in the third or fourth decade of life and there is often a notable dissociation between the advanced radiological findings and the mild clinical presentation. A positive diagnosis of PAM is reached by the combination of a positive chest radiograph and histological examination. Genetic testing may help to identify other latent patients in the family of the patient with PAM. In the present study, the cases of 3 patients diagnosed with PAM have been reported, including their clinical presentation, radio imaging, pathological symptoms, genetic test results and treatment plans, as well as the associated literature.