Pulmonary Alveolar Microlithiasis in a Middle-Aged Man Presenting With Respiratory Failure: A Case Report and Review of the Literature.

Pulmonary alveolar microlithiasis (PAM) is an autosomal recessive disease of the lung, characterized by diffuse deposits of intra-alveolar calcium phosphate microliths. It usually affects both sexes, presenting mostly in the second and third decades. The clinical course is highly variable, ranging from being asymptomatic to respiratory failure. PAM is usually diagnosed after careful clinical, radiological, and pathological evaluation, usually when patients present for other medical purposes. Here, a case of PAM in a middle-aged man presenting with acute-on-chronic hypoxemic respiratory failure is reported, with a review of the literature.