History:

A 53-year-old man presented with a 3.3 cm thyroid nodule. A prior FNA was diagnosed as suspicious for follicular neoplasm. Total thyroidectomy showed a solid mass with irregular peripheral borders. The neoplastic cells were positive for pancytokeratin, TTF-1, and PAX8, and negative for synaptophysin, chromogranin, p40 and calcitonin by immunohistochemistry.