Background: Pleuropericardial cysts are rare and usually clinically silent, but can occasionally cause life-threatening complications. The majority of them is congenital due to developmental deficits and is most commonly found incidentally via routine radiography between the third and fifth decade of life. Case Presentation: A 37-year-old Caucasian woman who referred to the Emergency Room because of asthma exacerbation diagnosed suffering of pneumonia. During the follow-up and after antibiotics, chest X-Ray and computed tomography revealed a probably acquired large pleuropericardial cyst of unknown cause. Conclusion: We report an unusual case of possible infection which revealed an asymptomatic large pleuropericardial cyst which was detected accidentally via X-Ray and was left untreated due to its benign course.

Keywords: Pleuropericardial cyst, asthma exacerbation, pneumonia, mediastinum