Pulmonary alveolar microlithiasis

**Definition:** Pulmonary alveolar microlithiasis is an idiopathic rare disease in which concretions composed of calcium and phosphorus collect in alveolar spaces. A systemic disorder of calcium metabolism has not been identified, and the serum calcium and phosphate levels are normal. Cough and dyspnoea are the most common presenting symptoms. Expectorated microliths have been reported. Inspiratory crackles, finger clubbing, and signs of cor pulmonale may be present in more advanced disease.