A variety of mediastinal masses may present in children. Imaging is generally confined to chest radiograph and CAT scan of the chest, although other studies may prove helpful depending upon the circumstances. MRI is particularly helpful for neurogenic tumors in the posterior mediastinum. The most common tumor in the anterior mediastinum is lymphoma with germ cell tumors second. In general, lymph nodes in areas outside the mediastinum provide access for tissue diagnosis when lymphoma is present. Germ cell tumors are generally benign, but surgical excision is indicated to rule out malignant elements and to treat symptoms which are often present through compression of nearby structures. Neurogenic tumors are the most common lesions in the posterior mediastinum.