Pulmonary Alveolar Microlithiasis : ?Sand Clock of Life??

Pulmonary alveolar microlithiasis is a rare diffuse lung disease which is characterized by deposition of calcispheres within alveoli. We present a case of a 38 years old female who presented with shortness of breath for last 3 years which has exaggerated in last one month. Chest radiograph showed multiple small nodules scattered in bilateral lung fields which were more predominant in lower zone. On HRCT, there were numerous dense, calcific nodules with predominance in subpleural region and basal segments which were forming confluence in basal segments bilaterally. Such advanced changes are rarely described in literature.