Brachial Plexitis during Maintenance Atezolizumab after Palliative Radiotherapy for Cervical Spine Metastasis in Lung Cancer.

We present the case of a patient with lung cancer who developed brachial plexitis following treatment with immunochemotherapy, which included atezolizumab and palliative radiotherapy for a metastatic cervical spine tumor. This case highlights the importance of considering immune-related adverse events (irAEs) when initiating immune checkpoint inhibitor therapy, in addition to other recognized causes such as radiation, tumor compression and invasion, and paraneoplastic syndromes. While brachial plexitis has been reported as an irAE associated with programmed cell death 1 (PD-1) antibodies, this is the first report associated with the administration of programmed cell death ligand 1 (PD-L1) antibodies.