A Rare Case of Superior Mediastinal Cyst in Pregnancy with Spontaneous Postpartum Disappearance

Bronchogenic cysts are congenital anomalies arising from abnormal budding of the tracheobronchial tree, typically requiring surgical intervention when symptomatic. We present an unusual case of a 29-year-old pregnant woman who presented with acute chest pain and shortness of breath, initially raising concern for pulmonary embolism. Computed tomography pulmonary angiography (CTPA) revealed a 5 cm bronchogenic cyst located posterior to the trachea, with no evidence of pulmonary embolism. The patient was managed conservatively with antibiotics and discharged with close monitoring. Remarkably, follow-up imaging after delivery demonstrated near-complete resolution of the cyst, which had decreased to 1 cm without any medical or surgical intervention. This case highlights the potential for spontaneous regression of bronchogenic cysts, possibly influenced by the physiological changes of pregnancy, and challenges the conventional approach of mandatory surgical excision for such lesions.