Answer and Discussion of Quiz Set: N-019

2.    Which of the following features is true regarding  diffuse astrocytoma (WHO grade II)?

A.  Some of these tumor can progress to higher grade tumor such as anaplastic astrocytoma and glioblastoma

B.  The incidence of this type of tumor in neurofibromatosis 1 and 2 (NF1 and NF2) is not increased

C.  Mutation of p53 can be demonstrated about 10% of these tumors

D.  The spinal cord is a common site

E.  Headache is a common symptom but seizure is not common

Answer and Discussion: The answer is (A). The mean survival time of patient with diffuse astrocytoma after surgical intervention is about 6-8 years with marked variation among individuals. Malignant transformation to glioblastoma typically occurs after a mean time interval of 4-5 years. There is, to this date, no validated predicting factor that would unambigously predicts the occurrence of malignant transformation. Young age at the time of diagnosis is a consistent positive predictive factor for better survival. The incidence of glial tumor is increased in both NF1 and NF2. Mutation of p53 can be seen in about 60% of the cases. The mutation rate in gemistocytic astrocytomas is over 80%. The incidence of astrocytoma in different parts of the brain is essentially proportional to the amount of white matter. Since the spinal cord is small, the incidence of astrocytoma in the spinal cord is also low. While headache is a common symptom, seizure is also a common symptom. New adult onset seizure should raise a serious concern of brain tumor but not necessary astrocytomas or gliomas.