Skin Metastases of Glioblastoma

Extra-cranial metastases of glioblastoma (GBM) are rare events, and the mechanisms involved in their development are still controversial and need further elucidations. Although because of their low frequency GBM metastases do not represent a rou- tinely therapeutic challenge in patients with GBM, such modality of tumour progression could be of cru- cial interest for the comprehension of the biology of GBM. More specifically, metastases of GBM to the skin have been reported in literature in very few and heterogeneous cases. We here review the state of the art of GBM skin metastases, focusing on the hypothesized mechanisms involved, as well as on the suggested diag- nostic and therapeutic approaches to these patients, and on the possible relevance of a “glial to mesenchy- mal transition” as a facilitating event involved in the extra-neural spreading of GBM.