Metastatic diseases of the central nervous system - neuropathologic aspects.

A large percentage of patients with cancer will develop brain metastases, and many of them will die within a few months following diagnosis of intracranial metastasis. Although the majority of the central nervous system metastases are derived from a well-known primary neoplasm, about 5-10% of brain metastases are from an unknown source, making the tissue diagnosis a first step in the search for a primary malignancy. The pathologist utilizes several immunohistochemical and molecular diagnostic tools for such investigation, helping the clinical oncologist to narrow down the clinical and radiologic exploration. Recently, analysis of actionable biomarkers for target therapy in brain metastasis has become significant due to reports of discrepancy of potential biomarkers between primary tumors and metastatic brain deposits.