There is extensive air density seen in the soft tissues of the anterior, lateral and posterior chest wall, dissecting into the deep soft tissue and muscle planes, and which extends superiorly and inferiorly to involve the left neck and left lateral abdominal wall, respectively. The emphysema even crosses over to the right side at the level of the thoracic inlet.
Within the lung fields, there is a large, well defined, cystic lesion measuring 16 cm (AP) x 9 cm (Trans) x 19 cm (CC) seen in the left lung, occupying almost the entire lung field. Within the dependant portion of this lesion, there is a heterogeneous, serpiginous or onion peel like nodule density. This is representative of the spin or Cumbo sign of detached or ruptured hydatid cyst membranes.
Pleural reaction posteriorly, as well as lung atelectasis medial to the cyst, are also seen, in keeping with the rupture.
Surrounding the hydatid cyst there are multiple smaller cystic cavities interspersed with areas of severe panlobular interstitial emphysema. Midline shift to the right is also seen, likely secondary to mass effect.
The right lung field is unaffected.