[Mature teratoma of the mediastinum: apropos of 2 cases].

Mature teratoma is the most frequent primary germ-cell tumor occurring in the mediastinum. These tumors present characteristic mature cells derived from all three types of embryogenesis tissues. We report two cases. The typical presentation is a cyst-like noninvasive, heterogeneous and calcified formation in the anterior mediastinum, usually in young subjects. Tumor markers, alpha-fetoprotein and beta-gonadotropin, are contributive as they rule out mature tumors if positive. Surgery is the treatment of choice, although adherence to neighboring structures usually makes complete excision difficult. Pathology provides the precise diagnosis, ruling out an immature component.