**Core Concept**
The question is testing the understanding of the characteristics of certain types of brain tumors, specifically their tendency to invade surrounding brain tissue through vacuolar spaces. This concept is crucial in neurosurgery and neurology for the diagnosis and treatment of these tumors.

**Why the Correct Answer is Right**
Vacuolar invasion is a hallmark feature of glioblastoma multiforme (GBM), a highly aggressive type of primary brain cancer. GBM cells have a strong propensity for invasion, which is facilitated by their ability to degrade the extracellular matrix and create vacuoles in the surrounding brain tissue. This invasion pattern makes GBM a challenging tumor to treat, as it can lead to rapid progression and poor patient outcomes.

**Why Each Wrong Option is Incorrect**
* **Option A:** Astrocytomas, including low-grade and high-grade varieties, can exhibit some degree of infiltration into surrounding brain tissue, but they are not typically characterized by vacuolar invasion.
* **Option B:** Medulloblastomas are highly aggressive brain tumors, but they tend to exhibit a more classical pattern of infiltration through the cerebellar cortex rather than vacuolar invasion.
* **Option C:** Ependymomas are a type of brain tumor that arise from the ependymal cells lining the ventricles and central canal of the spinal cord. While they can exhibit some degree of infiltration, they are not typically characterized by vacuolar invasion.

**Clinical Pearl / High-Yield Fact**
GBM is a World Health Organization (WHO) Grade IV astrocytoma, and its diagnosis is often made based on the presence of necrosis, microvascular proliferation, and a high number of mitotic figures.

**Correct Answer:** D. Glioblastoma multiforme.