Solitary mediastinal cystic lymphangioma is an extremely rare tumor-like abnormality of the lymphatic system, of congenital origin. From 1996 to 2003, 4 cases of solitary mediastinal cystic lymphangioma were managed in our department. The clinicopathologic characteristics were recorded and analyzed. The incidence proved to be 1.2% among all cases of mediastinal masses admitted to our department. All patients were asymptomatic, they shared common radiologic features, and all were managed by radical surgical excision. No recurrence or mortality were noted during follow-up ranging from 2 to 7 years. Complete excision of this benign entity has an excellent prognosis.