Pulmonary Alveolar Microlithiasis in an Elderly: A Case Report with Brief Review of Literature

Abstract

Pulmonary alveolar microlithiasis (PAM) is a rare chronic lung disease characterized by presence of widespread intraalveolar accumulation of innumerable minute calculi called microliths. It is caused by inactivating mutations in the gene "solute carrier family 34 member 2", encoding a sodium-dependent phosphate co-transporter (SLC34A2) expressed primarily in alveolar epithelial type II cells. It is most frequently diagnosed from birth to 40 years of age with a mean age of 27-30 years at the time of diagnosis. Most of patients are asymptomatic or having mild symptoms and are usually diagnosed incidentally. Chest radiograph and high-resolution CT of thorax are nearly pathognomonic for diagnosing PAM and histopathological confirmation is required only in few cases. This disease has slow progressive course ultimately leading to death by causing pulmonary fibrosis and cor pulmonale. Currently, there is no medical or gene therapy capable of reducing disease progression. Lung transplantation remains the only possible treatment for end-stage disease. Herein,we report a case of PAM in a 60-year-old gentleman who presented with a 5-year history of shortness of breath on exertion and intermittent cough with expectoration. His sister had similar respiratory symptoms and died 10 years back of which no details are available. The rarity of this disease and late age of presentation prompted us to report this case.