This case report demonstrates that ICI therapy-associated thyroid storm can arise not only from destructive thyroiditis but also from Graves' disease, highlighting that careful clinical evaluation is essential to determine the underlying pathophysiology and guide optimal management.
A man in his 80s with advanced lung cancer developed thyroid storm during treatment with immune checkpoint inhibitors nivolumab and ipilimumab.
Marked thyroid-stimulating antibody positivity indicated Graves' disease as the underlying mechanism, rather than the more commonly suspected destructive thyroiditis.
ICI-associated thyroid storm can arise through Graves' disease as a mechanism, not only through destructive thyroiditis.
Thyroid storm is a rare but recognized immune-related adverse event that can occur during immune checkpoint inhibitor therapy.
This research describes a rare and serious case involving an elderly man with lung cancer who developed a life-threatening thyroid crisis called 'thyroid storm' while being treated with cancer immunotherapy drugs (nivolumab and ipilimumab). These drugs, known as immune checkpoint inhibitors, work by unleashing the immune system to fight cancer, but they can sometimes cause the immune system to mistakenly attack the body's own organs, including the thyroid gland. The patient experienced dangerous symptoms including high fever, confusion, an irregular heartbeat, and an extremely overactive thyroid gland. What makes this case particularly notable is the identification of the cause. When the thyroid becomes overactive during immunotherapy, doctors typically assume it is due to 'destructive thyroiditis,' where the immune system damages thyroid cells causing them to leak thyroid hormone. However, blood tests in this patient showed high levels of thyroid-stimulating antibodies, pointing instead to Graves' disease — an autoimmune condition where antibodies directly stimulate the thyroid to produce excess hormone. This distinction matters because the two conditions may require different treatment approaches. This research suggests that when patients on immune checkpoint inhibitor therapy develop thyroid problems, clinicians should not automatically assume destructive thyroiditis is the cause. Testing for thyroid-stimulating antibodies may be important to correctly identify whether Graves' disease is involved, as this could change how the condition is managed. Given how widely immunotherapy drugs are now used in cancer treatment, awareness of this rare but serious complication — and the importance of identifying its exact mechanism — is clinically relevant.
Hagiwara J, Sekine M, Sakawaki E, Sakawaki S, Takeyama Y. (2026). Thyroid storm triggered by immune checkpoint inhibitor therapy.. BMJ case reports. https://doi.org/10.1136/bcr-2026-272027