In this group, pons was involved in 42 cases, midbrain in 8 and medulla in 1. Headache and vomiting were presented in 5 eases of the midbrain tumors initially and repeated attacks of vomiting were presented occasionally in medullo-pontine tumors.

• 病变累及桥脑者42例,仅侵犯中脑8例,累及延髓1例。