Dramatic clinical response in the treatment of small cell glioblastoma multiforme

What is known and objective: Small cell glioblastoma (scGBM) is a rare subtype of primary glioblastoma, which typically behave more aggressively compared with classical glioblastoma (GBMs). They are generally associated with poor responses to treatment, and optimal treatment is not known. Case summary: We present the case of a 51-year-old woman with scGBM with O⁶-methylguanine DNA methyltransferase (MGMT) promoter methylation, demonstrating an unexpected dramatic clinical response to chemoradiotherapy. What is new and conclusion: This case highlights that treatment with temozolomide-based chemoradiotherapy is justified in patients with scGBM, despite their poor prognosis. MGMT methylation may be associated with clinical responses.