Basal ganglia and thalamic tumours: an imaging approximation.

INTRODUCTION: Among brain tumours, those arising from the deep brain are rare. In many cases they are low-grade astrocytomas. But primitive neuroectodermal tumours, ganglion cell tumours, oligodendrogliomas, lymphomas, and germinal neoplasms can also grow up from the basal ganglia and thalamic region. In other occasions peripheral neoplasms developing in neighbouring structures like the cerebral lobes, the ventricular walls, choroidal plexus, pineal gland and the hypothalamic-chiasmatic-suprasellar region can spread to the deep brain.

IMAGING: Imaging cannot reliably indicate that a histological picture for a tumour of this kind should be suspected. Although the macro- and microscopical characteristics of brain tumours are often the basis of the imaging findings, these data usually overlap and are only useful as an approximation tool.

CONCLUSIONS: Nonetheless, whilst radiologists and clinicians must always be cautious when evaluating the macroscopic peculiarities of a brain tumour, the value of imaging cannot be overestimated when any sort of pathology is encountered. Moreover, besides the classic CT and MRI findings, new MRI-related techniques, such as magnetic resonance spectroscopy (MRS), are able to extract a different kind of information from cerebral neoplasms, and they could be important widespread diagnostic alternatives in the very near future.