An ultrastructural and cytoenzymological study on the folliculo-papillary thyroid carcinoma.

Authors studied ten cases of folliculo-papillary thyroid carcinoma, using ultrastructural methods and cytochemical techniques for peroxidase and acid phosphatase activities. The most striking ultrastructural features were: disappearance of secretory granules or apical vesicles; nuclei with an irregular shape containing stage I and II inclusions; two types of cells: with dilate endoplasmic sacks filled with a granular material, or rich in closely packed mitochondria, some of them showing dystrophic lesions with round, dense bodies or tightly packed parallel filaments and numerous phagolysosomes. The peroxidase activity was present as black DAB precipitates in the nuclear envelope and sometimes around colloid droplets, or was completely absent from some cells. The acid phosphatase activity was found as unhomogeneous Pb precipitates inside the lysosomes. The ultrastructural and cytoenzymological pattern suggests marked alteration of the synthesis, storage and secretion of the thyroid hormones. Keeping in mind that results of radio-iodine treatment depend mainly on the histologic type of the thyroid carcinoma, the cooperation between radiotherapeutist and pathologist is emphasized.