We retrospectively studied patients with NTRK fusion‐positive pediatric PTC who received the selective TRK inhibitor larotrectinib and had ≥1 year of follow‐up after treatment cessation….Patient D had a partial response (‐35%) after 8 months of larotrectinib, and after 13 months, 123I scan showed no uptake. 131I was not given and, 13 months after stopping larotrectinib therapy, the disease was unchanged....Larotrectinib reduced tumor size in TRK fusion‐positive pediatric PTC.