False-Positive Uptake of 131I From Basal Cell Papilloma in a Patient With Metastatic Papillary Thyroid Cancer

A 64-year-old woman with metastatic papillary thyroid cancer underwent a total thyroidectomy followed by 2 courses of 131I therapy. The posttherapeutic whole-body scan after the second dose of 131I therapy showed multifocal bone metastasis. In addition, there is focal abnormal intense radiotracer uptake at the right inguinal region. SPECT/CT revealed that this abnormal focal radioactivity was from a superficial skin lesion. Further physical examination revealed a raised, approximately 1-cm, irregular grayish-brown lesion on the right groin skin. Histopathological examination confirmed the diagnosis of basal cell papilloma (seborrheic keratosis).