Commonest intracranial tumour is?
**Core Concept**
The commonest intracranial tumour is a type of neoplasm that arises from the brain or its surrounding structures. This tumour type is often benign and may not cause symptoms in its early stages, but it can lead to significant morbidity if left untreated.
**Why the Correct Answer is Right**
The correct answer is a type of tumour that originates from the meninges, the protective membranes surrounding the brain and spinal cord. These tumours are typically slow-growing and can occur in any part of the central nervous system. The most common type of meningioma is the meningothelial meningioma, which accounts for approximately 40% of all meningiomas. Meningiomas are often associated with mutations in the NF2 gene, which is a tumour suppressor gene.
**Why Each Wrong Option is Incorrect**
* **Option A:** This is incorrect because gliomas are a type of primary brain tumour, but they are not the most common type of intracranial tumour. Gliomas arise from glial cells in the brain and can be benign or malignant.
* **Option B:** This is incorrect because acoustic neuromas are a type of vestibular schwannoma, which is a benign tumour that arises from the Schwann cells of the vestibulocochlear nerve. While they are common in the cerebellopontine angle, they are not the most common type of intracranial tumour.
* **Option C:** This is incorrect because pituitary adenomas are a type of endocrine tumour that arises from the pituitary gland. While they are common, they are not the most common type of intracranial tumour.
**Clinical Pearl / High-Yield Fact**
It's worth noting that meningiomas are often found incidentally on imaging studies, such as MRI or CT scans, and may not cause symptoms until they reach a large size. This is why it's essential to follow up with patients who have been diagnosed with meningiomas to monitor for any changes in their size or symptoms.
**Correct Answer: D. Meningioma. Meningioma**