Mediastinal Bronchogenic Cyst, Which Was Grown Rapidly

Bronchogenic cyst arises from anomalous budding of the primitive foregut during embryonic development and it represents a part of the spectrum of bronchopulmonary foregut malformations. Approximately two-thirds of the malformations are found within the mediastinum, and one-third are found in the lung parenchyma. The prevalence of bronchogenic cyst is unknown, presumably because most patients are asymptomatic. Incidentally detected bronchogenic cysts are usually removed at the time of diagnosis. We do not know how and why bronchogenic cysts grow. We recently experienced a case of rapidly growing mediastinal mass in a young adult, and this presented as a huge mass that had newly developed within one year. This mass was pathologically confirmed to be a bronchogenic cyst. We report on this case of a rapidly growing bronchogenic cyst, which is a rare characteristic of this type of cyst.