Comparative immunohistochemical study of normal, hyperplastic and neoplastic C cells of the rat thyroid gland

Abstract

In rats, the frequency of spontaneous C-cell tumours is very high and is both age and gender dependent. The three specific stages of neoplastic progression can be distinguished into diffuse C-cell hyperplasia, focal C-cell hyperplasia and bona fide C-cell tumours. Based on this hypothetical model of human medullary thyroid carcinoma (MTC), we carried out an immunohistochemical study using different markers (calcitonin, calcitonin gene-related peptide, somatostatin and chromogranin) to verify the existence of any relationship between their expression and the successive steps of tumour development. We found a characteristic immunohistochemical staining pattern, particularly for calcitonin and somatostatin, which distinguishes C-cell tumours from both normal and hyperplastic C cells, with no differences related to the gender of the animals under study. Specifically, a considerable heterogeneity in calcitonin expression was only displayed by C-cell carcinomas, being less pronounced in C-cell adenomas. As for somatostatin, this regulatory peptide was found only in a minority of calcitonin-positive cells in normal and hyperplastic glands. However, in some C-cell adenomas and most C-cell carcinomas nearly all calcitonin-positive cells also coexpressed somatostatin. We conclude that rat C-cell neoplasms constitute a very particular tumour entity which shares many but not all immunohistochemical features with human MTC.

Nonproliferative and Proliferative Lesions of the Rat and Mouse Endocrine System

“…( Boorman et al 1996 ; Botts et al 1991 ; Burek 1978 ; Capen et al 2001 ; Capen and Martin 1989 ; Crissman et al. 1991 ; Hardisty and Boorman 1990 ; Hardisty and Boorman 1999 ; Jokinen and Botts 1994 ; Kaspareit-Rittinghausen et al 1990 ; Kiupel et al 2008a ; Martín-Lacave et al 2002 ; Murthy 1990 ; Napalkov 1990 ; Pilling et al 2007 ; Rosol 2013 ; Van Zwieten et al 1983 ; Ward et al 1979a )…”

A Spontaneous Epithelial-Myoepithelial Carcinoma of the Submandibular Gland in a Sprague-Dawley Rat

“…In the present case, there were no histological findings suggestive of mammary gland tumors. A tumor of thyroid gland origin would be positive for calcitonin, a specific thyroid tissue marker, and a tumor of neuroendocrine origin would be positive for specific neuroendocrine tissue markers such as synaptophysin or chromogranin A 19 , 20 . However, the tumor cells in our case were negative for calcitonin, synaptophysin and chromogranin A.…”