Acquired thymic cysts are multilocular and show florid xanthomatous and myofibroblastic inflammation. They usually occur in association with mediastinal neoplasms, systemic autoimmune diseases, or trauma. We describe 2 cases (in a 12-year-old girl and an 11-year-old boy) of acquired thymic cysts occurring in association with cystic teratomas, an association that to our knowledge has not been described previously in the literature.