Mediastinal cysts : a 52-case retrospective study.

Introduction: mediastinal cysts are rare lesions developed from mediastinal structures. They may be acquired like thoracic duct cysts or lymphangiomas or congenital like the bronchogenic cysts, enteric cysts or celomic cysts. These cysts are rare and may cause diagnostic challenges.

Aim: To assess the major characteristics of these cysts based on a single institution experience.

Methods: the authors performed a descriptive, retrospective study from January 2009 to March 2020 in a single institution. Cystic lesions taking birth from the mediastinum for which gross features, microscopic features were available were included.

Results: this study contained 52 mediastinal cysts that were completely resected and no patient presented complications after the surgical resection. The bronchogenic cysts were the most frequent and represented 57.69% of all lesions. Thymic cysts and pericardial cysts represented respectively 40.38% and 1.92% of the cases. The positive diagnosis was based on the microscopic exam. The final diagnosis was concordant with the radiologic findings in 15 cases reaching a rate of 28%.

Conclusion: the diagnosis of mediastinal cysts is based on the microscopic analysis of the cystic wall. Pericardial cysts may be suspected based on their characteristic location in the cardiophrenic angle, thymic cyst may be evoked based on their location in the thymic region and bronchogenic cysts are mainly located in the middle mediastinum. Inspite of these most frequent locations, the cysts may be located in any part of the mediastinum and may be difficult to diagnose when the key diagnostic features are absent.