Fundamentals of neuropathology: Introduction to neuropathology and molecular diagnostics

Classification of central nervous system tumors has historically relied primarily upon morphologic features identified by light microscopy; however, in the past decade, integration of high-throughput genomic testing into routine clinical workflows has refined the approach to brain tumor diagnostics. In this chapter, we explore tumor classification from traditional microscope-based approaches to currently available methodologies, including genomic profiling, thereby introducing the concept of an integrated diagnosis. We begin with a discussion of the histologic assessment of brain tumors, which is often the first data to be reported after a tumor surgery. This is followed by a discussion of molecular profiling that is used to further classify these tumors, guide prognosis, and predict response to therapy and returns in the weeks following surgery. Finally, we review a series of common case scenarios and integrate the histologic and molecular data into a final integrated diagnosis that clinicians can use to help manage and counsel these patients.