Spontaneous Pneumothorax Revealing Pulmonary Alveolar Microlithiasis: A Case Report.

Pulmonary alveolar microlithiasis is a rare autosomal recessive lung disease characterized by intra-alveolar accumulation of calcium phosphate microliths. Diagnosis is often incidental on chest imaging, while histological examination remains the gold standard. We report the 15th case of pulmonary alveolar microlithiasis in Morocco, revealed by a complete spontaneous pneumothorax. A 61-year-old patient with a family history of chronic respiratory failure presented with acute chest pain and dyspnea. Chest radiography demonstrated diffuse micronodular opacities associated with a large pneumothorax. Initial management included pleural drainage; persistent air leakage required pleurodesis with simultaneous lung biopsies. Histopathological analysis confirmed the diagnosis by demonstrating intra-alveolar calcospherites. Two years after diagnosis, the patient reported exertional dyspnea. Pulmonary function testing demonstrated a restrictive pattern, and arterial blood gases revealed a PaO₂ of 73 mmHg, indicating mild hypoxemia. This case highlights the importance of histological confirmation in pulmonary alveolar microlithiasis, particularly in atypical presentations such as spontaneous pneumothorax.