Although INI1 deficiency is pathognomonic for ES, it is not exclusive to this entity and can also be observed in a spectrum of other malignancies, including malignant rhabdoid tumors, poorly differentiated chordomas, epithelioid malignant peripheral nerve sheath tumors, epithelioid schwannomas, soft tissue myoepithelial tumors, and SMARCB1-deficient sinonasal carcinoma [2]. The gene discussed is SMARCB1; the disease is Epithelioid Malignant Peripheral Nerve Sheath Tumor.