This 41 year-old male has respiratory failure and is awaiting a lung transplant. He presented with an infective exacerbation of his disease. The plain frontal chest xray shows mild hyperinflation, and a coarse pattern in the lung fields consisting of reticular interstitial markings and peripheral ring shadows suggesting cysts.

High resolution CT confirmed the presence of multiple small peripheral cystic lesions, some of which were branching and bizarre. There was honeycombing in the lower zones. There were a few small peribronchovascular nodules and there was interlobular septal thickening.

The differential diagnosis of multiple pulmonary cystic lesions includes Langerhan’s cell histiocytosis, lymphangiomyomatosis, sarcoidosis and lymphocytic interstitial pneumonitis. Peripheral bronchiectasis should be considered as it may appear cystic. Given the other changes seen on HRCT, and the patient’s sex, LCH was the favoured imaging diagnosis.

Reference: Webb WR, Higgins CB. Thoracic Imaging. Lippincott, Williams & Wilkins 2005

Credit: Dr Laughlin Dawes