RATIONALE: Drugs used in chemotherapy, such as hydroxyurea, work in different ways to stop the growth of tumor cells, either by killing the cells or by stopping them from dividing. Imatinib mesylate may stop the growth of tumor cells by blocking some of the enzymes needed for cell growth. It is not yet known whether hydroxyurea is more effective when given alone or together with imatinib mesylate in treating patients with meningioma.