[Mediastinal cystic lymphangioma; report of a case].

A cystic lymphangioma is a rare mediastinal benign tumor. A 38-year-old male was referred to our hospital because of an mediastinal mass incidentally detected on chest X-ray. The mass had enlarged rapidly during the course of 1 year. Computed tomography (CT) of the chest showed a 7 cm well defined cystic tumor in the left anterior mediastinum. Magnetic resonance imaging (MRI) demonstrated a mass with heterogeneous high signal intensity on enhanced T2-weighted images. The cystic tumor, localized in the mediastinal adipose tissue, was completely resected by a thoracoscopic procedure. A pathological examination confirmed the diagnosis of a cystic lymphangioma.