People in this study will visit the research center two times each month to see the study doctor. The study can last up to 2 years. Treatment happens in cycles, and each cycle is 28 days long, which is about 4 weeks. A person can have up to 26 cycles, which equals about 2 years of treatment. The amount of medicine given will depend on the person’s weight, which is checked before each new cycle. The medicine is called tocilizumab. It blocks a protein called interleukin-6, which causes swelling in the body. This medicine is usually used for diseases where the immune system attacks the body, like arthritis, and it can also help with a problem called cytokine release syndrome after certain cancer treatments.

This study is for a rare brain tumor called Adamantinomatous craniopharyngioma, or ACP. It is not cancer, but it mostly affects children.

Age: Patients must be at least 1 year old and no older than 39 years when they join.

Diagnosis: Patients must have a confirmed diagnosis of adamantinomatous craniopharyngioma (ACP).

This can be proven by looking at tumor tissue under a microscope.

If tissue cannot be safely taken, doctors may test cyst fluid. ACP cyst fluid is usually thick, cholesterol‑rich, and greenish‑brown.

Imaging scans should show a lobulated mass (part solid, part cystic) with calcifications in the sellar/suprasellar region of the brain.

Disease Status: Patients must have a tumor that can be measured on scans.

This study wants to learn how a medicine called tocilizumab works for people who have a brain tumor called Adamantinomatous craniopharyngioma, or ACP. Doctors will check both the good effects and the bad effects of the medicine.