ASCP Pathology Assistant Practice Exam

The most common form of intracranial tumor is a metastatic tumor. These types of tumors originate from cancer cells that have spread from other parts of the body to the brain. Common primary sources include cancers of the lung, breast, and skin (melanoma), which can invade the central nervous system and manifest as lesions in the brain. This process is known as metastasis, where malignant cells travel through the bloodstream or lymphatic system to secondary sites.

This prevalence is largely due to the higher incidence of systemic malignancies, along with the ability of these cancers to spread widely, affecting various organs including the brain. While gliomas and meningiomas are indeed significant categories of primary brain tumors, metastatic tumors account for a larger portion of intracranial neoplasms seen clinically, especially in adults. Meningiomas, while common as well, tend to be benign more often and are less frequent in overall incidence compared to metastatic lesions.