[Thirty-eight operative cases of mediastinal cyst: with particular reference to bronchogenic cyst].

Thirty-eight patients (16 males and 22 females) with mediastinal cysts have been treated at the Second Department of Surgery at Okayama University from 1978 to 1989. There were thirteen cases of thymic cyst, nine cases of pericardial cyst one case of pericardial diverticulum, eight cases of bronchogenic cyst, two cases of dermoid cyst, two cases of cystic lymphangioma, one case of esophageal cyst, one case of gastroenteric cyst, and one case of aneurysmal bone cyst. MRI seemed to be useful for the qualitative diagnosis of mediastinal tumors as cystic or solid. Based on Maier's classification and considering the result of this study, bronchogenic cysts may be divided into the following groups: 1) paratracheal, 2) carinal, 3) hilar, 4) paraesophageal [a) upper (Iu), b) lower (Im, Ei)], 5) cephalad recess of the azygos vein (CRAzV) and 6) miscellaneous. According to this new classification, these bronchogenic cysts could be allocated to (3) hilar: 1 cyst, (4-a) paraesophageal-upper: 1 cyst, (4-b) paraesophageal-lower: 1 cyst, (5) CRAzV: 4 cysts, and (6) miscellaneous: 2 cysts.