Pericystic emphysema in pulmonary hydatid disease

The case of a 12-year-old Caucasian boy, living in a non-endemic area, with two intrapulmonary masses is presented. Conventional X-rays and computed tomography images were highly suggestive of pulmonary Echinococcus disease because of the presence of pericystic emphysema in one of both masses, a finding known as the "crescent" or "meniscus" sign. This radiological feature and other highly suggestive imaging findings of pulmonary hydatid disease are presented and discussed.