Pulmonary Alveolar Microlithiasis: A Rare Genetic Lung Disease Mistaken for Miliary Tuberculosis—A Case Report

REPORTbases.Chest radiograph showed bilateral diffuse micronodular opacities with obliteration of diaphragm and cardiac borders (Fig. 1A).High-resolution computed tomography (HRCT) scan of the chest revealed bilateral lower lobe predominant interlobular septal thickening and diffusely distributed multiple random micronodules (Figs 1C and D).Dense calcification was noted in the costal, diaphragmatic, and mediastinal pleura along with calcification of subpleural lung parenchyma in the lower lobes (Fig. 1B).Her serum electrolytes (calcium and phosphorus), vitamin D levels, intact parathormone levels, and alkaline phosphatase were within normal limits.Testing for human immunodeficiency virus (HIV) by enzyme-linked immunosorbent assay (ELISA) was negative.Her sputum microbiological analysis for tuberculosis (AFB smear and GeneXpert MTB/RIF) was negative.She could not perform spirometry and did not consent for bronchoscopic lavage and lung biopsy.The whole-exome sequencing done, which revealed a homozygous mutation in SLC34A2 gene (c.675G>A),confirmed the diagnosis of PAM in our case.She was treated