22 Neurosurgery MCQs Answers

Answer: b, c, e

Astrocytomas arise from the glial (stromal or supporting) cells of the brain. These tumors are infiltrative and rarely can be totally excised. High-grade astrocytomas (grades III and IV) are the most common primary intracranial tumor constituting 25% of all intracranial tumors and 50% of all gliomas. For the most part meningiomas are benign tumors that arise from the arachnoid layer of the meninges occurring in the fourth through sixth decades of life. Meningiomas can occur in a variety of sites and together constitute about 17% of intracranial tumors. The treatment for meningiomas is surgical, however, total resection is uncommon, frequently resulting in recurrence. Malignant histologic appearance of meningiomas is far less common than a benign appearance. Schwannomas are benign tumors that arise from the Schwann cells that surround axons as they leave the CNS by way of the cranial nerves. Schwannomas constitute 8% of all intracranial tumors and are almost twice as common in females as males. Medulloblastomas are part of the primitive neuroectodermal classification of brain tumors. They are thought to arise from primitive cells of the cerebellum, most likely the external granular layer. They constitute 8% of all gliomas. Two-thirds of medulloblastomas occur in children, with the average age of onset being 14 years. They commonly metastasize throughout the subarachnoid space by way of the CSF and are rarely found outside the CNS. Treatment involves aggressive surgical removal of the tumor followed by radiation of the brain. Chemotherapy is commonly used as well. Craniopharyngiomas are histologically benign and arise from nests of squamous cells within the pituitary gland. They may be found in the intrasellar or suprasellar locations but are always along the craniopharyngeal canal. Over 50% occur in the first two decades of life. Although craniopharyngiomas can be cured with surgical removal or controlled with radiation, many of these histologically-benign tumors cannot be removed safely.

Category: Surgery MCQs