Brain Stem Gliomas - Hannah's final diagnosis
Brain stem gliomas account for 20% of childhood tumors and just short of 5% of adult tumors. They most frequently afflict children between the ages of 3 and 10 years and they range from very low-grade astrocytomas, like the juvenile pilocytic astrocytoma, to the rapidly growing anaplastic glioblastoma multiforme. They are named by their location at the base of the brain rather than the cells they contain. The symptoms of this tumor may include nausea, headache, speech or balance abnormalities, difficulty with swallowing and weakness or numbness of the arms or legs. In some patients, the symptoms of the tumor develop insidiously and as much as a year passes before they are recognized. In others, symptoms develop abruptly, a pattern that tends to relate to more rapidly growing tumors. Surgery is not usually used to treat brain stem gliomas because of their vulnerable location. Radiation therapy sometimes helps to reduce symptoms and improve survival by slowing tumor growth. Tumors in this region of the brain are uniformly dangerous, but those of a low grade may have very long periods of remission.

JPA - Hannah's first diagnosis
The juvenile pilocytic astrocytoma (JPA) is a common tumor of childhood, although it occasionally occurs in adults. While it may arise in any area of the brain, it frequently occurs in the cerebellum and often is surrounded by a capsule-like cyst. Its symptoms include headache, nausea, vomiting and problems with muscle coordination (ataxia). This is one of the low-grade gliomas. It is very slow-growing and often can be cured with surgery alone. When a JPA occurs in another area of the brain, such as the optic chiasm, it is sometimes impossible to totally remove surgically because of its location. Under such circumstances, it may be treated with either radiation therapy or chemotherapy.

The above information was found at www.braintumor.org.