[C-cells in malignant epithelial tumors of the thyroid gland]

An original procedure using points to evaluate the degree of tumor cell differentiation was employed in examining patients with papillary (42), follicular (33), medullary (19) and anaplastic (2) thyroid cancer. C-cell hyperplasia was detected in 26 out of the total of 94 cases (27.6%). It was the backdrop for each form of thyroid cancer and increased as tumor cell differentiation decreased. Three grades of C-cell hyperplasia were identified: I--11-20; II--21-49 and III--over 50 cells. According to anaplastic degree, it was typical and atypical; according to spreading pattern--focal, diffuse and nodular. Typical or diffuse hyperplasia was detected in well-differentiated cell tumor, while the atypical pattern prevailed in poorly- and moderately-differentiated ones. Most attention should be given to cases of subcapsular atypical hyperplasia of small C-cells showing initial well-differentiated cells of medullar thyroid cancer (C-cell microcarcinoma).