The anterior mediastinum is located posterior to the sternum and anterior to the pericardium, between the fourth and seventh ribs. Biopsies from the anterior mediastinum can be challenging as this location may harbor many lesions, including primary and metastatic tumors. It can be the site for the development of primary epithelial, mesenchymal, lymphoid, neurogenic, and germ cell neoplasms. The diagnoses of these lesions can be made using a variety of techniques including radiologically guided fine needle aspiration, core needle biopsies or surgical biopsy through anterior mediastinotomy, mediastinoscopy, median sternotomy, or thoracotomy. More recently, transesophageal endoscopic ultrasound-guided fine needle aspiration and endobronchial ultrasound-guided transbronchial needle aspiration biopsy have been described as alternative methods with high levels of sensitivity and specificity.

CYSTS

Bronchogenic cyst

Clinical features

Mediastinal cysts comprise approximately 13% of total mediastinal mass lesions. Bronchogenic cysts are closed sacs considered to be the result of an abnormal embryonic budding of the respiratory system, and are the most common of the mediastinal cysts. They are seldom seen in the adult, and most are thought to be asymptomatic and free of complications.

Radiologic features

Computerized tomography (CT) reveals round, well-circumscribed masses of water density, while magnetic resonance imaging (MRI) shows bright signal intensity in T2-weighted images. If symptoms are present, the most common are retrosternal chest pain and dyspnea.