The patient was a boy aged 15 months at the time of enrollment with a phosphodiesterase 4D‐interacting protein (PDE4DIP)–NTRK1 fusion, localized, intramuscular soft‐tissue sarcoma…The patient received 2 cycles of ifosfamide and etoposide. She had an inadequate response and subsequently initiated treatment with larotrectinib. She achieved a confirmed partial response with a 93% reduction in tumor burden and was referred for surgery after 14 cycles of larotrectinib.