Lymphangiomas in the mediastinum are rare benign tumors, characterized proliferating lymphatic vessels. They are usually found in children and young adults, but rarely in order adults. Most are located in the neck, with less than 1 percent found in the mediastinum, with mediastinal lymphangiomas comprising 0.7-4.5 percent of all tumors in this location. They are often classified pathologically according to the size of the cystic spaces within them, as simple or capillary, cavernous and cystic, or just cystic, hygromas, Of the 3 types above, the cavernous type of mediastinal lymphangioma is very rare. We report a case of a mediastinal lymphangioma of the cavernous type that was confirmed from pathological findings, a CT and MRI scan.