Abstract
Contamination of external sites with secretions or excretory products can mimic metastases and yield false positives in radioiodine whole-body scintigraphy for thyroid cancer. We present a case of a 26-year-old woman with differentiated papillary thyroid carcinoma who received radioiodine 131 (I-131) for treatment of persistent upper mediastinal metastasis. Her post-treatment whole-body scintigraphy revealed an unexpected focus of increased uptake near the scalp in addition to the mediastinal lesion. Although the scalp is the most common site of cutaneous thyroid cancer metastasis, differentiated thyroid cancers rarely manifest with cutaneous thyroid cancer metastasis and thus it is prudent to consider etiologies of false positive I-131 uptake in such cases. Contamination of our patient’s hair from salivary secretions was confirmed on history and with coiffure repositioning during whole-body scintigraphy.