Skin metastases of glioblastoma in the absence of intracranial progression are associated with a shift towards a mesenchymal immunophenotype: report of two cases

Glioblastoma multiforme (GBM) is the most malignant astrocytic tumour. Extra-neural spread is exceedingly rare, and usually develops at the time of intracranial progression following a surgical procedure [2–4]. Less frequently, metastases are a consequence of spontaneous tumour transdural extension or haematogenous spread. Here, we describe two unusual cases of GBM in which scalp metastases appeared in the absence of intracranial disease progressio