Pulmonary alveolar microlithiasis—a rare lung disease—diagnosed by transbronchial cryobiopsy

Pulmonary function tests showed a restrictive ventilatory defect with forced vital capacity of 2·18 L (66% predicted) and transfer factor—also known as the diffusing capacity of the lungs for carbon dioxide—of 24% predicted. [...]as genetic testing was not available to us and bronchoalveolar lavage was negative for microliths, we decided, with the patient's consent, to do transbronchial cryobiopsy to confirm our clinical diagnosis. [...]under total intravenous anaesthesia with endotracheal intubation, transbronchial cryobiopsy was done, with no complications, using a 1·7 mm flexible cryoprobe and a prophylactic balloon blocker, guided by fluoroscopy, with a single 5-sec activation in the lateral segment of the right lower lobe. PAM is a rare hereditary lung disease characterised by autosomal recessive inheritance, resulting from a loss-of-function mutation in the SLC34A2 gene that causes an abnormal accumulation of calcium phosphate deposits in the lungs.