Calcitonin-negative primary neuroendocrine tumor of the thyroid (nonmedullary) in a dog

• Main Authors: E.A. Soler Arias, V.A. Castillo, M.E. Caneda Aristarain
• Format: Article
• Language: English
• Published: Tripoli University 2016-11-01
• Series: Open Veterinary Journal
• Subjects: Calcitonin-negative; Immunohistochemistry; Ki-67; Medullary thyroid carcinoma; Neuroendocrine
• Online Access: http://www.openveterinaryjournal.com/2016/Volume%206%20(3)/OVJ-113-05-16%20E.A.%20Soler%20Arias%20et%20al.pdf

The Calcitonin-negative neuroendocrine tumor of the thyroid (CNNET) or "nonmedullary" in humans is a rare tumor that arises primarily in the thyroid gland and may be mistaken for medullary thyroid carcinoma; it is characterized by the immunohistochemical (IHC) expression of neuroendocrine markers and the absence of expression for calcitonin. An Argentine dogo bitch showed a solid, compact thyroid tumor, which was IHC negative for the expression of calcitonin, carcinoembryonic antigen, thyroglobulin and S100 protein, and positive for synaptophysin and cytokeratin AE1-AE3. The Ki-67 proliferation index was low. We cite this case not only because it is the first case report of calcitonin-negative primary neuroendocrine tumor of the thyroid in dogs but also because we want to highlight the diagnostic importance of IHC in this regard.