Mediastinal Hydatidosis with an Unusual Presentation

Hydatidosis is a common zoonotic disease with a high prevalence in developing countries. While a solitary cyst with unilateral lung involvement is common, bilateral involvement and multiple cysts are rare, only seen in 20% and 30% of the cases, respectively. 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 patient. She presented in the year 2020 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 lesions with internal echoes throughout the mediastinum, lung, pericardium, diaphragm and chest wall were observed in contrast-enhanced computed tomography of the thorax. An incidental cystic lesion in the liver was also noted. Since serology for echinococcosis was negative, a differential diagnosis of intrathoracic malignancy was considered. However, intraoperative and histopathologic findings were suggestive of hydatidosis.