Bronchogenic cysts are congenital malformations that are thought to develop from abnormal budding of the embryonic foregut. They are most commonly seen in the mediastinum, especially in the middle and the posterior mediastinum, and they typically show water-attenuation. Anterior mediastinal bronchogenic cyst is extremely rare. Anterior mediastinal bronchogenic cysts with soft-tissue attenuation have not been reported in the English-language literature up until now. We discovered 3 cases of anterior mediastinal well-circumscribed lesions showing soft-tissue attenuation which were diagnosed as thymoma preoperatively, but were later identified as bronchogenic cysts on pathology.