Diagnostic Images of Pulmonary Alveolar Microlithiasis: A Rare, Autosomal Recessive Disorder

Pulmonary alveolar microlithiasis (PAM) is a genetic lung disorder that is characterized by the accumulation of calcium phosphate deposits in the alveolar spaces of the lung. PAM is discovered incidentally on radiographs performed for other purposes, and the typical disease course is characterized by slowly progressive respiratory failure over decades. Treatment remains supportive. A 62-year-old woman presented in the emergency department with dyspnoea and fatigue. On physical examination she had crackles on pulmonary auscultation and digital clubbing. A CT scan of the chest showed multiple high-density areas throughout the lung parenchyma, suggesting the presence of alveolar microlithiasis. This CT finding is the typical radiological presentation of PAM, while the hallmark presentation is clinical–radiological dissociation. LEARNING POINTS: Pulmonary alveolar microlithiasis (PAM) is a rare genetic lung disorder resulting in accumulation of calcium phosphate deposits in the alveoli. The typical radiological presentation of PAM is the classic ‘sandstorm’ appearance in the lung. The key to diagnosis of this disease is clinical-radiological dissociation.