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Question 7#

The most common malignant tumor of the brain is:

A. Ependymoma
B. Astrocytoma
C. Ganglioglioma
D. Teratoma

Correct Answer is B

Comment:

Astrocytoma is the most common primary central nervous system (CNS) neoplasm. The term glioma often is used to refer to astrocytomas specifically, excluding other glial tumors. Astrocytomas are graded from I to IV Grades I and II are referred to as low-grade astrocytoma, grade III as anaplastic astrocytoma, and grade IV as glioblastoma multiforme (GBM). Prognosis varies significantly between grades I/II, III, and IV, but not between I and II. Median survival is 8 years after diagnosis with a lowgrade tumor, 2 to 3 years with an anaplastic astrocytoma, and roughly 1 year with a GBM. GBMs account for almost twothirds of all astrocytomas, anaplastic astrocytomas account for two-thirds of the rest, and low-grade astrocytomas the remainder. Figure below demonstrates the typical appearance of a GBM.

A. Postcontrast Tl -weighted axial magnetic resonance imaging (MRI) demonstrating a ring-enhancing lesion in the anteromedial right temporal lobe with centra l necrosis (dark area) consistent with glioblastoma multiforme. B. T2-weighted axial MRI with extensive bright signal signifying peritumoral edema seen with glioblastoma multiformes.