Co-existing pulmonary hydatid cyst with aspergillosis.

Pulmonary hydatid cyst is known to occur, but incidental detection of Aspergillus colonisation in an unruptured cyst wall, especially in immunocompetent patients, is very rare. Presentation can be hemoptysis or asymptomatic, depending upon immune status. Colonisation of the cyst wall may be due to immune dysregulation, structural abnormalities, invasion of fungal organisms through channels between airways and cyst and other mechanisms. Here, we report a rare case of Aspergillus colonisation in the hydatid cyst wall in a young immunocompetent patient and also try to describe the pathogenetic mechanism for the same.