Zur Kenntnis und Problematik des hellzelligen Adenomes in der Schilddrüse

Summary

A retrospective study of 4271 surgical specimens from the thyroid gland revealed 2 morphologically benign and 6 obviously malignant clear-cell tumors. In one case, origin of the carcinoma from the thyroid gland was proven by autopsy, and another case was classified as clear-cell carcinoma of the thyroid gland because its metastases took up radioiodine.

In two cases thyroid nodules were believed to be late metastases from clear-cell carcinomas of the kidney operated on some time before. In two other cases a carcinoma of the kidney was detected after extirpation of the thyroid nodules. According to morphological criteria two cases were classified as clear-cell adenomas. This rare variant of thyroid tumor is not generally considered to be benign and remains open to discussion. Clear-cell adenoma of the thyroid gland does not contain lipids or glycogen in neoplastic cells, but exhibits a characteristic ultrastructure. The cytoplasm is filled with smooth surfaced empty vesicles which are believed to derive from the Golgi apparatus. Vesicular degeneration of the cytoplasm seems to be responsible for the clear aspect of the tumor cells in histological examination. Thus the thyroid clear cell seems to be a very rare but characteristic element in neoplasia of the follicular epithelium, and might be analogous to the oxyphil cell. Criteria for the diagnostic differentiation and problems of the different clear-cell tumors of the thyroid gland are discussed.