Herein, we reported the case of a 32-year-old male patient presented with intermittent attacks of mild right chest pain and dyspnea for 2 years. On contrast-enhanced computed tomography (CT) of the chest, a non-enhancing subcarinal cystic lesion about 6×6.5 cm was detected in the posterior mediastinum, consistent with the features of bronchogenic cyst. The lesion showed small calcific focus changing its position posteriorly when patient changes his position from supine to prone. The flecks of calcium within the fluid in a cystic lesion constitute the origin of the future cyst wall calcifications and may reflect the long-standing nature of the lesion. Surgical excision is preferred to avoid the expected complications, including fistula formation, ulceration, and infection.
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