A rare case of opaque hemithorax

Opaque hemithorax itself presents a plethora of causes. The physicians often mistook opaque hemithorax as massive pleural effusion. But rare causes of opaque hemithorax should also be explored. Hydatidosis is one of the rare causes of opaque hemithorax. Hydatidosis remains the endemic disease in some regions of the world. The liver and the lungs are the most affected sites in adults. Very few cases have been described in literature regarding hydatid cysts presenting as opaque hemithorax. A 20-year-old nonsmoker male admitted in our hospital with complaints of shortness of breath and cough for the last 1 year. Chest x-ray was suggestive of left opaque hemithorax with contralateral mediastinal shift. Ultrasonography of the chest revealed multiple anechoic cystic lesions of varying size. Computed tomography chest suggested the presence of multiple multiloculated cystic lesions in the entire left hemithorax. Transthoracic needle aspiration fluid cytology gave the suspicion of parasitic cyst. On further workup, the hydatid serology was found to be positive. Our patient presented with opaque hemithorax, and further workup leads us to the diagnosis of pulmonary hydatidosis.