Pulmonary alveolar microlithiasis. State-of-the-art review

Pulmonary alveolar microlithiasis (PAM) is a rare genetic lung disease characterized by calcifications within the alveoli. Mutations in the SLC34A2 gene, which encodes a type IIb sodium-phosphate cotransporter, are responsible for this disease, leading to intra-alveolar accumulation of phosphate that favors the formation of microliths. The hallmark of this disorder is clinical-radiological dissociation, with typical imaging findings that correlate well with specific pathological findings. The long-term prognosis is poor and no treatment has been discovered to date. The aim of this review is to describe the main pathological, clinical, and imaging aspects of PAM, ranging from its genetic basis to treatment.