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Radioactive Iodine Scintiphotos of a Man With Thyroid Cancer

Images of a man with thyroid cancer indicated abnormal iodine localization. Can you guess the cause?

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The contemporary management of differentiated thyroid cancer includes posttreatment monitoring for recurrence or metastasis.1 This monitoring includes clinical, biochemical, and imaging evaluation. Follow-up treatment can then be tailored based on the results of this monitoring.

Our patient was a 61-year-old man with a history of papillary thyroid carcinoma, including lymph node involvement and an extension of the primary focus into skeletal muscle (pT3N1bMX, stage IVa). The patient’s status was posttotal thyroidectomy and radioiodine ablation therapy (196.2 mCi iodine-131) in April 2009. The patient underwent follow-up thyrotropin alpha stimulated whole-body radioiodine surveillance scanning in May 2010.

Images demonstrated residual thyroid tissue/carcinoma regional to the thyroid bed, corresponding to prior posttherapy images. Whole body scintiphotos also demonstrated abnormal iodine localization that raised the possibility of distant bony metastasis in the region of the right hip (see Figures 1A and 1B). Current treatment standards for isolated bony metastases recommend repeated radioactive iodine therapy and potential external beam radiation. Imaging is required for accurate verification.1 This abnormal osseous finding was questionable on initial review, as it was present on the posterior, not anterior, view. The patient was instructed to continue hydration and return for additional delayed scintiphotos for further evaluation.

The patient returned 4 days later for delayed scintiphotos, which again demonstrated abnormal iodine localization near the right hip. However, iodine distribution was different, including now being visible on both the anterior and posterior views (see Figures 2A and 2B on the next page).

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  • How would you treat this patient?

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