IMMTs, now categorized under the “Intracranial mesenchymal tumor, FET::CREB-fusion-positive” category of the 2021 WHO Classification of Tumors of the Central Nervous System [50], are tumors of mesenchymal, nonmeningothelial origin with varying morhpological characteristics [79]. The gene discussed is CREB1; the disease is mesenchymal cell neoplasm.