SS18 and mesenchymal cell neoplasm: The absence of myogenic markers helped to exclude alveolar rhabdomyosarcoma, while ‘next‐generation immunohistochemistry’, which exploits the molecular genetics of mesenchymal neoplasms, including SS18‐SSX and DUX4, helped to rule out synovial sarcoma and CIC‐rearranged sarcomas, respectively.