Calcitonin-negative neuroendocrine tumor of the thyroid with metastasis to liver-rare presentation of an unusual tumor: A case report and review of literature

Figure 2 Thyroid pathology and immunohistochemistry. A: Tumor cells are arranged in a beam-shape with obvious cell atypia and thick chromatin (Hematoxylin eosin staining, 200 ×); B: Negative calcitonin staining of tumor cells (Immunohistochemistry (IHC) staining, 200 ×); C: Positive TTF-1 staining of tumor cells (IHC staining, 200 ×); D: Positive CgA staining of tumor cells (IHC staining, 200 ×); E: Positive Syn staining of tumor cells (IHC staining, 200 ×); F: 20% Ki67 staining of tumor cells (IHC staining, 200 ×).