E.A. Soler Arias(1,*), V.A. Castillo(1) and M.E. Caneda Aristarain(2)
1 Hospital Escuela, Unidad de Endocrinología, Area de Clínica Médica de Pequeños Animales, Fac. de Ciencias Veterinarias, UBA, Av. Chorroarín 280, Ciudad Autónoma de Buenos Aires, Argentina
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.
Keywords: Calcitonin-negative, Immunohistochemistry, Ki-67, Medullary thyroid carcinoma, Neuroendocrine.
Soler Arias, E.A., Castillo, V.A. and Caneda Aristarain, M.E. 2016. Calcitonin-negative primary neuroendocrine tumor of the thyroid (nonmedullary) in a dog. Open Vet. J. 6(3), 223-227.