ABSTRACT
A 44-year-old man developed coronavirus disease 2019 (COVID-19) pneumonia during immunochemotherapy consisting of carboplatin, paclitaxel, and pembrolizumab for non-small cell lung cancer. Low-grade fever, followed by mild hypoxemia, and febrile neutropenia, were observed, and granulocyte colony-stimulating factor (G-CSF) was administered until the recovery of neutropenia, when he developed a high fever, severe hypoxemia, and hypotension accompanied by consolidation in the bilateral lungs. His conditions promptly improved after treatment including hydrocortisone and the primary and metastatic tumors remained regressed for 10 months without further treatment. Post-COVID-19 organizing pneumonia during cancer immunochemotherapy can be aggravated by immune-checkpoint inhibitors and G-CSF.