pubmed-article:2712868 | pubmed:abstractText | We studied five cases of poorly differentiated follicular or papillary thyroid carcinomas. Immunohistochemical study revealed numerous ACE positive cells, also positive for calcitonin, ACTH, somatostatin or several of these peptides. These tumors containing both vesicular component and parafollicular cells are endocrine tumors of "mixed" or "intermediate" type. The diagnosis must be confirmed by immunohistochemistry but can be suggested by histological findings: abundant fibrous stroma, trabeculovesicular pattern, and swelled moderately acidophilic cells neighbouring vesicular cells. These facts argue in favor of a common-embryological origin of vesicular and parafollicular cells from ultimobranchial undifferentiated cells. Nevertheless such tumors must take place in thyroid neoplasia's classifications and an appropriate terminology remains to be precised. | lld:pubmed |