Kucukarda, AhmetGokmen, IvoOzcan, ErkanPeker, PinarAkgul, FahriCicin, Irfan2024-06-122024-06-1220221750-743X1750-7448https://doi.org/10.2217/imt-2021-0275https://hdl.handle.net/20.500.14551/18814Introduction: The case of a patient who developed recurrent delayed immune-related pneumonitis (checkpoint inhibitor pneumonitis [CIP]) after immune checkpoint inhibitor (ICI) therapy for advanced osteosarcoma treatment is presented. Case summary: A 25-year-old female patient with metastatic osteosarcoma was treated with atezolizumab. Grade 2 pneumonitis developed three times in the first two years. Treatment was discontinued after recovery from the last episode of pneumonitis, which was complicated with secondary spontaneous pneumothorax. 2 years after discontinuation of immunotherapy, the patient again developed CIP. Pneumonitis symptoms were regressed with oral steroid therapy during follow-up and a stable disease response continued. Conclusion: Immunotherapy can cause recurrent CIP at any time during the treatment period or after discontinuation of treatment. Plain language summary Immune checkpoint inhibitors have been used in many types of cancer because they cause prolonged tumor responses. However, new side effects associated with these drugs have been identified. Pneumonia of the lung tissue may occur and recur during the use of these drugs or after their discontinuation. Patients with newly developing pulmonary symptoms during follow-up should be carefully monitored for this side effect.en10.2217/imt-2021-0275info:eu-repo/semantics/closedAccessAtezolizumabDelayed Immune-Related Adverse EventsImmune-Checkpoint InhibitorsImmunotherapyRecurrent PneumonitisAdverse EventsArticle146395399Q4WOS:0007546712000012-s2.0-8512615246735152716Q2