Analysis of lectin binding in benign and malignant thyroid nodules.

The lectin binding properties of ten cases each of adenomatoid nodule, follicular adenoma, and papillary carcinoma and five cases of microinvasive follicular carcinoma were examined histochemically and compared with adjacent normal thyroid tissue. Wheat germ agglutinin, concanavalin A, Ulex europaeus agglutinin I, peanut agglutinin, soybean agglutinin, Dolichos biflorus agglutinin, Ricinus communis agglutinin, and Helix pomatia agglutinin were employed. All the lectins but Ulex europaeus agglutinin I, peanut agglutinin, and Helix pomatia agglutinin were bound to thyroid parenchymal cells, colloid and stromal cells, but none uniquely to thyroid parenchymal cells. Helix pomatia agglutinin binding was present in stromal cells but not in parenchymal cells. Ulex europaeus agglutinin I binding to parenchymal cells was weakly positive only in five cases of papillary carcinoma. The binding in adenomatoid and neoplastic cells and their colloid was stronger than in adjacent normal thyroid tissue in all cases examined. Wheat germ agglutinin and concanavalin A binding was most intense among the lectins examined. In papillary carcinoma, lectin binding was observed mostly in the apical cytoplasm of carcinoma cells, whereas a diffuse surface binding pattern was predominant in follicular adenoma and carcinoma, adenomatoid nodules and normal thyroid gland. No consistent differences in lectin binding were found between follicular adenoma and carcinoma, or between adenomatoid nodules and follicular neoplasia.