Abstract
Background. Pulmonary alveolar microlithiasis (PAM) is a rare autosomal recessive lung disease caused by biallelic pathogenic mutations in the SLC34A2 gene, leading to calcium phosphate microlith accumulation in alveoli.Methods. We report a case of suspected PAM-like disease during pregnancy with postpartum histopathologic and genetic evaluation.Results. A 26-year-old pregnant woman presented with spontaneous left-sided pneumothorax at 16 weeks' gestation. Imaging revealed bilateral reticulonodular opacities with a characteristic sandstorm appearance. High-resolution CT confirmed widespread intra-alveolar calcifications. Lung biopsy showed intra-alveolar ossification with focal marrow elements and hemorrhage, without classic laminated microliths. Genetic testing identified a heterozygous missense SLC34A2 mutation (c.1110A>G; p.Ile370Met), previously reported in patients with PAM. Although a second pathogenic allele was not identified, the genetic findings were considered supportive but not diagnostic.Conclusions. This case highlights spontaneous pneumothorax as a rare initial presentation of a PAM-like phenotype, particularly in pregnancy. It underscores the diagnostic challenges posed by atypical histology and incomplete molecular confirmation.