Primary Thoracic Wall Hydatid Cyst Extended to the Abdominal wall: A Case Report.

Hydatid disease (HD) is an infectious disease caused by echinococcosis. Hydatid cyst (HC) most commonly invades the liver (60-70%) and the lungs (20-25%). However, other parts of the body and even unusual locations can be infected, mimicking a benign lesion that could be easily missed. Primary HC of the chest wall is extremely rare, even in countries where echinococcosis is endemic. We herein present a case of a 40-year-old man with a right-sided growing thoracic wall mass. The patient did not present the relevant history (living in rural areas or being in contact with farm animals) and the serological examination with the indirect hemagglutination test was negative. During surgery, a cystic mass between the eleventh and twelfth ribs was observed. The thoracic wall mass extended to the posterior abdominal wall and was entirely extrapulmonary and extraperitoneal. All cystic structures of the thoracic wall and intrathoracic region were removed, and the primary defect was reconstructed. In endemic areas such as Iran, HD should be considered in the differential diagnosis of mass lesions located in the chest wall or other parts of the body, even without the relevant history or serologic evidence.