Primary glioblastomas have a worse prognosis and different tumor biology, and may have a different response to therapy, which makes this a critical evaluation to determine patient prognosis and therapy. Over 80% of secondary glioblastomas carry a mutation in IDH1, whereas this mutation is rare in primary glioblastoma (5–10%). Thus, IDH1 mutations are a useful tool to distinguish primary and secondary glioblastomas,  since histopathologically they are very similar and the distinction without molecular biomarkers is unreliable. Prevention
There are no known methods to prevent glioblastoma. It is the case for most gliomas, unlike for some other forms of cancer, that they happen without previous warning and there are no known ways to prevent them. Treatment
Treating glioblastoma is difficult due to several complicating factors:
The tumor cells are resistant to conventional therapies. The brain is susceptible to damage from conventional therapy. The brain has a limited capacity to repair itself. Many drugs cannot cross the blood–brain barrier to act on the tumor.Treatment of primary brain tumors consists of palliative (symptomatic) care and therapies intended to improve survival. Symptomatic therapy
Supportive treatment focuses on relieving symptoms and improving the patients neurologic function. The primary supportive agents are anticonvulsants and corticosteroids. Historically, around 90% of patients with glioblastoma underwent anticonvulsant treatment, although only an estimated 40% of patients required this treatment. Recently,  neurosurgeons have been recommended that anticonvulsants not be administered prophylactically, and should wait until a seizure occurs before prescribing this medication.
Systematized epidermal nevus is a cutaneous condition, an epidermal nevus with a diffuse or extensive distribution involving a large portion of a persons body surface. : 771

See also
Linear verrucous epidermal nevus


== References ==