Cancer around the brain.

BACKGROUND Neuro-oncologists are familiar with primary brain tumors, intracerebral metastases meningeal carcinomatosis and extracerebral intracranial tumors as meningeoma. For these conditions, and also some other rare tumor entities several treatment options exist. Cancer can also involve structures around the brain as the dura, the base of the skull, the cavities of the skull and tissue around the bony skull, the skin, the tissue of the neck. and either compress, invade or spread in the central or peripheral nervous system. METHODS A systematic literature research was conducted determining symptoms and signs, tumor sites of nerve invasion, tumor types, diagnostic techniques, mechanisms of nerve invasion, and important differential diagnosis. Additional cases from own experience were added for illustration. RESULTS The mechanisms of tumor invasion of cranial nerves is heterogenous and not only involves several types of invasion, but also spread along the cranial nerves in antero- and retrograde fashion and even spread into different nerve territories via anastomosis. In addition the concept of angiosomas may have an influence on the spread of metastases. CONCLUSION In addition to the well described tumor spread in meningeal carcinomatosis and base of the skull metastases, dural spread, lesions of the bony skull, the cavities of the skull and skin of the face and tissue of the neck region need to be considered, and have an impact on therapeutic decisions.