A 63-year-old woman presents with a several-week history of headaches and difficulties with speech. A sister who lives with her claims that her language "has recently not been making much sense" and that she is a bit confused. Her condition seems to be deteriorating. On neurologic examination, she has a moderately severe aphasia, with difficulty understanding language and following commands, and she makes frequent paraphasic errors when she speaks. There are no other motor or sensory deficits. An MRI with intravenous contrast reveals the presence of a ring-enhancing mass lesion within the substance of the left temporal lobe. The lesion is approximately 3 cm in great-est diameter, poorly demarcated from the surrounding brain, and surrounded by a moderate amount of cerebral edema. Findings on routine admission tests, including a chest x-ray and serum chemistry, are unremarkable. What is the most likely diagnosis?
High-Yield Explanation
Glioblastoma multiforme is a highly malignant neoplasm, arising from glial cells or their precursors within the CNS. It is the most common of all primary malignancies of the CNS and its peak incidence is within the fifth to sev-enth decade of life. A low-grade astrocytoma is a tumor derived from glial cells of astrocytes. Fig. 11-4, shows a large cystic giant astrocytoma on T2 weighted MRI where fluid is shown as a white area with midline shift (not glioblastoma multiforme presented in this question).