What is typically true about a meningioma?

A meningioma is typically characterized as encapsulated. This means that it is usually well-defined and surrounded by a layer of tissue, which helps in distinguishing it from surrounding structures. The encapsulation allows for a clearer surgical resection compared to tumors that infiltrate nearby tissues. Meningiomas predominantly arise from the meninges, which are the protective membranes covering the brain and spinal cord, and their encapsulated nature is a hallmark that can assist in diagnosis through imaging studies.

In contrast, the other characteristics mentioned are less accurate for meningiomas. They are not typically metastatic since they usually originate within the meninges itself rather than spreading from other areas of the body. Meningiomas also tend to grow slowly rather than rapidly, which is a key aspect of their behavior. Furthermore, they are not infiltrating tumors; rather, they tend to push against the brain or spinal cord without extensively invading the surrounding neural tissues. This distinction is crucial for both understanding their pathology and planning effective treatments.