Distribution of calcitonin-containing parafollicular cells of the thyroid in patients with chronic lymphocytic thyroiditis: a clinical, pathological and immunohistochemical study.

The C-cell hyperplasia of the thyroid gland is recognized as precursor to medullary carcinoma, particularly in multiple endocrine neoplasias, however it can be associated with hypercalcemic states and follicular tumours as well. The authors analysed 46 of their cases with Hashimoto's and/or lymphocytic thyroiditis from the immunohistological point of view with the aim of determining to what extent is C-cell hyperplasia associated with these pathological pictures. C-cell hyperplasia was demonstrated on sections of intraoperative preparations with the immunoperoxidase method with anticalcitonin MoAb. Moderate, focal C-cell hyperplasia was found in 17.4% (8 patients), extensive focal hyperplasia similarly in 17.4% (8 patients). Diffuse C-cell hyperplasia occurred in 1 case (2.2%). These results suggest the possibility that in the case of diffuse or more pronounced focal hyperplasia the serum calcitonin concentration of these patients is also elevated. Further clinical and pathological studies are needed to find out whether there is some pathogenetic relationship between chronic lymphocytic thyroiditis and C-cell hyperplasia or whether the finding is coincidental, and to establish what degree of C-cell hyperplasia is associated with elevated serum calcitonin levels. This relationship has been unknown until the present time, whereas it can be of great clinical significance, in part because of the changes in serum calcitonin levels, in part for screening out the MEN IIa type and working out the operating strategy.