[A case report of a bronchogenic cyst of the diaphragm causing rupturing into the left pleural cavity]

A rare case of a bronchogenic cyst of the diaphragm was reported. The patient was a 56-year-old woman complaining of epigastric pain. A CT scan and a MRI examination revealed a cystic tumor at the left vertebro-phrenic angle. The cyst ruptured into the left pleural cavity causing chest pain and consequently reducing its size. As the cyst had enlarged again after 6 months, she received surgical treatment and the tumor was totally removed. The cyst was monolocular, originating from the diaphragm and proved to be bronchogenic cyst. It had bronchial epithelium, smooth muscle, bronchial gland and cartilage histologically. Japanese literature on the bronchogenic cysts of the diaphragm were discussed. Seven cases, including this case, of bronchogenic cysts of the diaphragm have been reported in Japan. It is rare for bronchogenic cysts to rupture into the pleural cavity.