Case report: Two rare new cases of diaphragmatic bronchogenic cysts.

The bronchogenic cyst (BC) is a type of congenital anomaly that is most usually found in the mediastinum and lung, and rarely in the diaphragm. We report two cases of bronchogenic cysts originating from the left diaphragm. Case 1 involved a 50-year-old man who underwent computed tomography (CT) of the adrenal glands for hypertension, showing left adrenal changes. An adrenal CT at our hospital showed a space-occupying lesion above the left diaphragm. We performed a left-sided thoracotomy in the seventh intercostal space and found that the mass was entirely located in the diaphragm. Case 2 was a 58-year-old woman who underwent chest CT under a standard health check-up, and a subpleural lesion of approximately 4 cm was found in the posterior basal segment of the left inferior lung lobe. During thoracoscopic surgery, the mass was found to originate from the surface of the diaphragm, having no correlation with the lung tissue. The two cases of diaphragmatic bronchogenic cysts were confirmed by surgical pathology. Ectopic bronchogenic cysts arising from the diaphragm are very uncommon, and diaphragmatic bronchogenic cysts typically occur on the left side, in women, and in the angle between the vertebral column and the diaphragm. As far as we know, there are no relevant reports of intradiaphragmatic BCs similar to case 1, which was entirely located within the diaphragm. Most diaphragmatic BCs are located on the surface of the diaphragm and project toward the thoracic or abdominal cavities. Moreover, bilocular diaphragmatic bronchogenic cysts, similar to case 2, have not yet been reported.