Chest ultrasound findings in pulmonary alveolar microlithiasis

Pulmonary alveolar microlithiasis (PAM) is a rare disorder of unknown etiology affecting people at any age. It is characterized by multiple and microscopic calcium deposits diffusely localized within the alveoli. Thorax high-resolution computed tomography is considered the gold standard for PAM imaging. Herein we report for the first time the use of trans-thoracic ultrasound (TUS) examination in a young severely obese PAM female patient, diagnosed at the age of 10, and referred to our clinic for re-staging purposes at the age of 36. Unlike expected, no reverberation or additional artifacts were appreciated on TUS examination despite the severity of the interstitial/alveolar involvement seen on conventional CT imaging. To date, no ring-down or comet-tail artifacts were detected. The only TUS finding was an increased thickness and irregular profile, more evident in the dorsal lower lung regions, of the hyper-echoic pleural line. TUS has recently aroused increasing interest among clinicians and radiologists as a useful noninvasive diagnostic tool for studying pleuro-pulmonary diseases, including interstitial lung diseases (ILDs). The peculiarity of our case is represented by the discrepancy between TUS and CT findings. Further efforts to address the usefulness and US patterns in diffuse ILDs, with the inclusion of rare disorders, are needed.