Metastatic glioblastoma multiforme on skin and subcutaneous tissue

Abstract

Glioblastoma multiforme (GBM) is characterized by its infiltrative growth pattern and high recurrence rate despite treatment. While local progression within the central nervous system (CNS) is the rule, manifestations outside the CNS, particularly skin and subcutaneous metastases, are very infrequent and seldom reported in the literature. The authors reviewed the current understanding of this rare condition, with the main purpose of giving visibility to its clinical presentation and prognostic implications, thus improving clinical management and encouraging research in this area. A PubMed, Cochrane Library, and EMBASE search from database inception through March 2024 was conducted. In this way, we compiled a total of thirty-five cases in our review. As far as we know, our work gathers the largest number of patients with this condition. Remarkably, we observed that the typical presentation of soft-tissue high-grade glioma metastases is the finding of subcutaneous erythematous nodules in patients previously operated on for a primary CNS tumor, within the craniotomy site and nearby, mostly in the first year after the initial surgery. It was also noted that there is a trend of developing a concomitant CNS recurrence and/or other metastases in different locations, either simultaneously or subsequently. From here, we propose some possible mechanisms that explain the extracranial spread of GBM. We concluded that a poor outcome is expected from the diagnosis of skin and subcutaneous metastases: the mean overall survival was 4.38 months. Yet, assessing individual characteristics is always mandatory; a palliative approach seems to be the best option for the majority of cases.

Keywords

• glioblastoma
• metastasis
• scalp
• subcutaneous
• skin