Pseudoprogression

**Semantic type:** Finding

**Definition:** A radiologic finding observed during magnetic resonance imaging of brain glioblastoma, following concurrent radiotherapy and temozolomide treatment or vaccine therapy. It refers to the false positive finding of progression and enhancement of the lesion. It is considered a treatment effect due to tumor cell necrosis and subsequent edema formation and increased vascular permeability.

**Synonyms:** - PPD-Pseudoprogression - PSEUDOPROGRESSION - PsP