Abstract
Radiation-induced sarcoma (RIS) has been reported as a late secondary malignancy following radiotherapy for various types of cancer with a median latency of 10 years. We describe an early RIS that developed in an adolescent within three years of treatment (including PD-L1 check-point inhibitor Nivolumab) of a relapsed classic Hodgkin lymphoma (HL) and was diagnosed post-mortem. The patient died of the progressive RIS that was misleadingly assumed to be a resistant HL based on the positive PET/CT scan. Repetitive tumor biopsies are warranted in cases of aggressive and multi-drug resistant HL to validate imaging findings, ensure correct diagnosis and avoid overtreatment.