Honeycomb cysts in idiopathic pulmonary haemosiderosis: high-resolution CT appearances in two adults.

Idiopathic pulmonary haemosiderosis (IPH) is characterized by recurrent episodes of pulmonary haemorrhage. The disease predominates in childhood, with approximately 20% of patients presenting in adulthood. Most patients present with dyspnoea, fatigue and recurrent haemoptysis, resulting in iron deficiency anaemia. High-resolution CT manifestations of IPH include patchy or diffuse ground glass opacity and consolidation resulting from alveolar haemorrhage. We describe a new high-resolution CT finding in two adults with IPH - multiple honeycomb cysts, which were characteristically focal and localized predominantly to the posterior and lateral basal segments. We suggest that the development of honeycombing in patients with IPH is a traction phenomenon resulting from recurrent haemosiderin deposition in the interstitium, which is known to lead to progressive fibrosis. These honeycomb cysts may indicate the sites of the most severe and recurrent alveolar haemorrhage in adults with IPH.