Khaladkar Sanjay Mhalasakant, Kondapavuluri Sushen Kumar, Kamal Anubhav, Kalra Raghav, Kuber Rajesh
Department of Radiodiagnosis, Dr. D. Y. Patil Medical College and Research center, Pimpri, Pune, India.
J Radiol Case Rep. 2016 Jan 31;10(1):14-21. doi: 10.3941/jrcr.v10i1.2528. eCollection 2016 Jan.
Pulmonary alveolar microlithiasis (PAM) is a rare chronic lung disease characterized by deposition of intra alveolar calcium and phosphate in bilateral lung parenchyma with predominance in lower and mid zones. Etiology and pathogenesis is not fully understood. However, mutation in SLC34A2 gene that encodes a sodium phosphate co-transporter in alveolar type-II cells resulting in formation and accumulation of microliths rich in calcium phosphate due to impaired clearance is considered the cause of disease. Patients with PAM are asymptomatic till development of hypoxemia and cor pulmonale. It remains static, while in some it progresses to pulmonary fibrosis, respiratory failure and cor pulmonale. We report a case of 44 year old male patient presenting with progressive shortness of breath on exertion for one year in duration with dry cough, more since last six months. Chest radiograph showed dense micronodular opacities giving classical sandstorm appearance. High resolution computed tomography (HRCT) showed microcalcification, subpleural cystic changes and calcified pleura. Lung biopsy showed calcospherites within alveolar spaces.
肺泡微石症（PAM）是一种罕见的慢性肺部疾病，其特征是双侧肺实质内肺泡内钙和磷酸盐沉积，以下部和中部区域为主。病因和发病机制尚未完全明确。然而，编码肺泡Ⅱ型细胞中钠磷酸盐共转运体的SLC34A2基因突变，导致由于清除受损而形成和积累富含磷酸钙的微石，被认为是该病的病因。PAM患者在出现低氧血症和肺心病之前通常无症状。病情保持稳定，而在一些患者中会进展为肺纤维化、呼吸衰竭和肺心病。我们报告一例44岁男性患者，持续一年出现进行性劳力性气短，伴有干咳，近六个月加重。胸部X线片显示密集的微结节状阴影，呈现典型的沙尘暴外观。高分辨率计算机断层扫描（HRCT）显示微钙化、胸膜下囊性改变和钙化胸膜。肺活检显示肺泡腔内有钙球。
