Brain metastases with exceptional features from papillary thyroid carcinoma: report of three cases.

We present three papillary thyroid carcinoma PTC patients with brain metastases who are unusual in many aspects. The first case is a unique 3mm papillary thyroid microcarcinoma (PTMC) patient with metastases to the cerebrum and lung. The solitary cerebral lesion was identified by iodine-131 whole- body scan ((131)I-WBS) and (131)I single photon emission tomography/computed tomography (SPET/CT). Almost complete response achieved after radiosurgery. The second case is a unique PTC patient with coexistent (131)I-negative cerebrum, adrenal gland and ilium metastases, which were identified by (18)F-fluorodeoxyglucose ((18)F-FDG) positron emission tomography/computed tomography (PET/CT) and magnetic resonance imaging (MRI). Partial response achieved after radiosurgery. The third case is a patient with an incident solitary cystic cerebellar mass as a primary presentation of follicular variant of PTC and absent other distant metastases. In conclusion, widespread metastases from small PTMC may occur. Concomitant brain and adrenal metastases may occur in a same PTC patient. Brain metastasis may present as a cystic lesion.