On immunohistochemical (IHC) staining, tumor cells showed patchy expression of CD56, but the tumor was negative for broad-spectrum keratins, PAX8, TTF1, thyroglobulin, calcitonin, HBME-3, CEA, PTH, GATA3, p63, SOX10, and S-100. Here, TTF1 is linked to neoplasm.