C-cell hyperplasia and medullary thyroid carcinoma in the rat. An immunohistochemical and ultrastructural analysis.

摘要: Medullary thyroid carcinoma (MTC) is a distinctive neoplasm which derived from the calcitonin-producing intrathyroidal C-cell system and develops commonly in untreated rats of various strains. Thyroid glands Long-Evans ranging age 3 months to years showed spectrum proliferative abnormalities. As compared 3-month-old control rats, thyroids 9- 12-month-old animals exhibited mild diffuse hyperplasia (CCH). Thyroids 1 progressively more severe abnormalities including CCH, nodular and/or MTC. In contrast normal basal serum calcitonin levels controls with or MTC had elevated values. Nodular CCH was characterized by replacement enlargement individual follicles C-cells. Larger foci were similar changes multiple adjacent an irregular expansion follicles. penetration follicular lamina C-cells extension into stroma. addition high incidence thyroidal abnormalities, parathyroid found. There no evidence chronic renal failure these animals, calcium within limits. Although stimulus for initial proliferation remains unknown, appearance preceded relatively prolonged phases CCH. These findings are essentially identical those noted human familial indicate that rat provides useful model studying regulation during processes neoplastic development progression.