Spontaneous (Hashimoto-like) chronic lymphocytic thyroiditis in a rhesus macaque (<i>Macaca mulatta</i>)

Abstract. A case of a female, 10-year-old rhesus macaque (Macaca mulatta) with spontaneous chronic lymphocytic thyroiditis is presented. At necropsy, the thyroid gland was slightly enlarged, up to 2 mm large, round, confluent, beige foci on surface both lobes. Histopathologic features resembled human Hashimoto's thyroiditis: multifocally, interstitium infiltrated by lymphocytes and variably sized lymphoid follicles. In pituitary gland, there were increased numbers basophilic cells throughout adenohypophysis. Using electrochemiluminescence immunoassay (ECLIA), no autoantibodies against thyroglobulin, peroxidase, or thyroid-stimulating hormone receptor detected.