Programmed Death-1 Inhibitor Immunotherapy-Induced Symptomatic Toxic Thyroid Nodule.

Immune checkpoint inhibitors, specifically programmed death-ligand 1 (PD-LI) inhibitors, are immune modifying medications that increasingly treat specific types of cancer. They are known to cause many side effects, including thyroid-related side effects. The use of PD-L1 inhibitors can cause hypothyroidism most commonly, while hyperthyroidism occurs less frequently.