Metastatic Thyroid Carcinoma in Man Concentrating Iodine Without Organification

Abstract

A metastatic thyroid carcinoma in man was observed. It appeared 30 yr. after X-ray therapy of endemic goiter. One of the numerous metastases concentrated radioiodine without organisation. The accumulation of 1131 attained a value approximately 10 times lower than in normal thyroid gland. The effective half-time was 10-17 hr. The accumulated radioactivity was completely discharged after administration of potassium perchlorate. The discharge phenomenon was demonstrable even on the 5th day after perchlorate administration. This suggested some other mechanism of action than competition. The radioiodine was present in the tissue in a water extractable, dialyzable, nonprecipitable form. Iodinated proteins and amino acids were absent. In spite of negative suppression and stimulation tests, other findings suggest hormonal dependency of the growth and function of the tumor. The tumor was composed of compact clear cells without follicles and without PAS [periodic acid Schiff] positive colloid. This confirms the intracellular localization of the iodine-concentrating mechanism.