Lectin histochemistry of the thyroid gland

The authors carried out a histochemical study with lectins (Ulex europaeus agglutinin-I [UEA-I], Triticum vulgaris [WGA], Glycine max [SBA], Dolichos biflorus [DBA], and Arachis hypogaea [PNA]) in different thyroid gland conditions (17 benign nodular goiters, three diffuse hyperplasias, five Hashimoto's thyroiditis, 20 follicular adenomas, 14 well-differentiated papillary carcinomas, five well-differentiated follicular carcinomas, and 30 normal thyroids) in order to determine if specific lectin patterns are developed during neoplastic transformation. The results showed that (1) in normal thyroid glands, the lectin, UEA-I, is able to discriminate between follicular cells and C-cells; (2) pathologic follicular epithelium had an increased expression of UEA-I, SBA, and WGA receptors; (3) no lectin or group of lectins allow a distinction between follicular carcinoma and papillary carcinoma; (4) when benign and malignant tumors are compared for UEA-I affinity there is a significantly greater frequency of malignant tumour with UEA-I receptor; and (5) although all investigated lectins have shown receptors in endothelial cells at least in one case, the most constant findings have been obtained with UEA-I and WGA. These findings suggest that lectins are not useful in routine diagnostic pathologic examination; however, in particular cases of follicular carcinoma, UEA-I may be a useful tool for the recognition of small vessels invaded by tumoral cells and the demonstration of fucose residues in malignant tumor cells.