The Brain Adjacent to Tumor (BAT)

Gliomas represent the classical intra-axial tumors of the brain and glioblastoma multiforme (GBM) is the most frequent and malignant glioma. It is an extremely aggressive tumor with a high invasive potential. After treatments, it invariably resumes proliferation and its recurrences occur most often within 2 cm from the resection margins (Hochberg & Pruitt, 1980; Wallner et al., 1989; Oppitz et al., 1999). The dispersion of glioma cells in the surrounding normal brain puts them out of reach of surgery, radioand chemotherapy, because outside of the limits of surgical resection and of the irradiated volume, established in order to avoid damages to the normal brain. The BAT, therefore, is the place where tumor cells migrate and invade and where a series of biological, pathological and molecular events occur as far as the interaction between host and tumor is concerned. Migrating cells from the tumor, reacting astroglia and microglial cells, elements of the immunological response or belonging to the monocytic phagocyting system reaching the tumor from the blood flow, and cells from gliogenetic zones of the brain make the BAT a melting pot of interactions among cells and factors. It has special importance also from the neuroimaging point of view for the recognition of the tumor limits and of peritumoral edema, which may have, at the same time, a prognostic significance (Ramakrishna et al., 2010). With MRI, beside the peripheral increase of T2 signal, uptake of gadolinium, hypodensities corresponding to vasogenic edema, necrotic cyst formation, other features can be shown by special technical procedures. The correlation, therefore, between neuroimaging and histopathology and molecular biology in the BAT is of the greatest interest.