A 30-year-old man diagnosed with follicular thyroid carcinoma treated previously with total thyroidectomy was referred to radioiodine treatment. Post-therapy scan performed 10 days after a 150 mCi 131NaI revealed radioiodine uptake in left temporal region. To elucidate the abnormal head uptake, Tc-99m MDP bone scan and head magnetic resonance image was performed. No anomalous uptake was observed in the bone scan. Head magnetic resonance image found a well-circumscribed lesion in temporal was compatible with a vascular malformation. Angioresonance confirmed the diagnosis of cavernous angioma, a benign vascular tumor.