Pulmonary alveolar microlithiasis (PAM) (MIM 265100) is a rare, autosomal recessive pneumopathy characterized by intra-alveolar formation and accumulation of tiny, roundish corpuscles called "microliths". The name "alveolar microlithiasis" was first used by Puhr in 1933; since then, several reports have appeared, and over 300 individuals with this condition have been reported. We have reviewed the PAM cases in the literature in light of personal experience, focusing on medical implications, disease diagnosis and progression over time, familial predisposition, and geographical and sex distribution. This study confirms autosomal recessive inheritance and does not support the role of other, non-genetic, factors in the pathogenesis of PAM.