Pulmonary Alveolar Microlithiasis

Pulmonary alveolar microlithiasis (PAM) is a rare, chronic lung disease characterized by extensive intra alveolar calcium and phosphate deposition throughout both lung parenchyma. Etiology and pathogenesis of PAM is not known. There are some hypothesis for etiology and pathogenesis of PAM but none of them are satisfactory. The incidence of PAM is high in countries such as Turkey, Italy and USA. There is a surprising discordence between radiological appereance and clinical presentation. Chest X-ray appearance of PAM is almost pathognomonic. Patients with PAM may have all findings of interstitial lung disease in varying degrees as well as micronodules on their HRCTs. Patients with PAM usually asymptomatic untill the underlying process affects alveolar gas exchange however patients may ultimately develop hypoxemia and cor pulmonale. A definitive therapy for PAM did not exist. Patients with advanced lung disease may benefit from lung transplantation.