Hydatidosis is a common zoonotic disease with high prevalence in developing countries. While solitary cyst with unilateral lung involvement is common, bilateral involvement and multiple cysts are rare, seen in 20% and 30% of the cases. Likewise, extensive involvement of extrapulmonary tissues and mediastinum is rare. We report an unusual case of mediastinal hydatidosis mimicking an intrathoracic malignancy in a 24-year-old female. She presented with a history of left-sided chest pain and heaviness in the left hemithorax for a period of two months. Diffuse, multiple fluid-filled cystic lesion with internal echoes throughout the mediastinum, lung, pericardium, diaphragm and chestwall were observed in contrast-enhanced computed tomography of the thorax. An incidental cystic lesion in liver was noted. Since serology for echinococcosis was negative, a differential diagnosis of intrathoracic malignancy was considered. However, intraoperative and histopathologic findings were suggestive of hydatidosis.

Hydatidosis is a common zoonotic disease with high prevalence in developing countries. While solitary cyst with unilateral lung involvement is common, bilateral involvement and multiple cysts are rare, seen in 20% and 30% of the cases. Likewise, extensive involvement of extrapulmonary tissues and me...