Thyroid storm caused by metastatic papillary thyroid carcinoma tissue after total thyroidectomy: a case report

Thyroid storm is a life-threatening form of thyrotoxicosis and an endocrinological emergency. We present a case of thyroid storm in a patient with metastatic papillary thyroid cancer. A 67-year-old woman with a history of total thyroidectomy 4 years prior to presentation was admitted with deteriorating mental status, fever, and tachycardia. Laboratory tests revealed severe thyrotoxicosis. Although the patient had no residual thyroid tissue after total thyroidectomy, she had a previously diagnosed metastatic thyroid cancer lesion in the pelvic bone. Despite initial treatment with a standard thyroid storm regimen, the patient died 6 days after hospitalization. The patient had no history of Graves disease; however, a thyroxine receptor antibody was detected postmortem. The patient had a history of exposure to an iodine contrast agent, which is a rare cause of thyrotoxicosis. Thyroxine production from a differentiated thyroid carcinoma is rare but can be a source of clinically significant thyrotoxicosis in patients post-thyroidectomy. Overlapping Graves disease is a common stimulus; however, other causes, such as exogenous iodine, cannot be excluded. This case demonstrates that in the setting of metastatic thyroid carcinoma, thyrotoxicosis cannot be completely ruled out as a cause of suspicious symptoms, even in patients with a history of total thyroidectomy.