PAX8 and differentiated thyroid carcinoma: The 6 papillary CNS metastases had a complete prior workup with IHCs confirming their origin, such as TTF1 and thyroglobulin for papillary thyroid carcinoma, TTF1, CK7, CK20 for lung adenocarcinoma, and Pax8, WT1, CK7, CK20 for serous carcinoma of the ovary.