The reactions of euthyroid and hyperthyroid glands to radioactive iodine.

BACKGROUND: Researchers generally assume that the thyroid gland reacts more or less comparably to external irradiation and radioactive iodine. DESIGN: The thyroid glands from 20 euthyroid patients and 20 hyperthyroid patients, all of which had been treated with radioactive iodine, were studied. RESULTS: The two groups manifested different reactions. Almost all the euthyroid glands displayed a fibrotic atrophic pattern, whereas the glands from the Graves' disease patients showed more adenomatous and Hashimoto lesions than atrophy. CONCLUSION: Differences in the reactivity of normal and hyperplastic follicles may cause different reactions to treatment with radioactive iodine.

Correlation of thyroglobulin measurements and radioiodine scans in the follow-up of patients with differentiated thyroid cancer.

Correlation of radioiodine (131I) scans and serum thyroglobulin (Tg) concentrations were performed in the follow-up of 85 differentiated thyroid cancer patients who had undergone total thyroidectomy. Tg results were also compared with the control group of 33 thyroidectomized patients with no evidence of thyroid carcinoma and normal values for Tg established. Excellent correlation between Tg and scans was noted in patients with scan evidence of metastasis distant from the neck. Poor correlation was present in patients with scan evidence of local neck metastasis only, thyroid bed activity, and those with mediastinal activity. In addition, in 8% of the patients, the Tg assay could not be performed because of interfering antibodies. The conclusion is that elevated Tg concentration is a good indicator of metastasis outside of the neck as detected by 131I scans. Caution should be used when Tg alone is used in evaluating local neck metastasis demonstrated on scans. The significance of mediastinal activity warrants further investigation.

A safe technique for thyroidectomy with complete nerve dissection and parathyroid preservation.

A series of 1,000 consecutive thyroid operations is presented, without a case of permanent recurrent laryngeal nerve injury. Emphasis is placed on the identification of variations and complete dissection of the recurrent laryngeal nerve, including peripheral branches and technical aspects of the dissection. Sixty-five percent of the cases had multiple terminal branches of the recurrent laryngeal nerve and five cases on the right side had a nonrecurrent course. A low incidence of hypoparathyroidism is presented, due in part to the avoidance of ligating the inferior thyroid artery in continuity and the technique of extracapsular dissection of the thyroid gland. The external branch of the superior laryngeal nerve was protected by the early mobilization of the superior thyroid vessels and ligatures placed flush on the capsule of the superior pole.

The significance of 1-131 scan dose in patients with thyroid cancer: determination of ablation: concise communication.

Twenty-four patients with differentiated thyroid cancer were studied with diagnostic I-131 neck chest scans after having undergone bilateral subtotal thyroidectomy and initial I-131 therapy with either 30- or 100-mCi doses. With an endogenous stimulation protocol, follow-up studies were performed with neck and chest scans using 2 and 10 mCi I-131. A 400% increase in sensitivity was found with a 10-mCi dose relative to a 2-mCi dose. Comparison with therapeutic doses of 30 and 100 mCi resulted in further increases in the detection of residual iodine-avid tissue. We conclude that a 2-mCi or lower dose of I-131 is inadequate in evaluating residual iodine-avid tissue visually in patients with thyroid cancer. The study does not answer the critical question of whether it is necessary to treat a patient presenting a negative 2-mCi but a positive 10-mCi scan. It may be appropriate to define ablation visually as well as clinically, with further studies directed toward determining a treatment rationale in this patient population.

Occult medullary carcinoma of thyroid: an unusual clinical and pathologic presentation.

High calcitonin levels noted on a totally healthy 49-year-old man participating in a calcitonin control project led to a presumptive diagnosis of medullary carcinoma. Complete thyroid studies augmented by selective catheterization and quantitative calcitonin studies confirmed the clinical impression of medullary carcinoma. Surgery was recommended and a total thyroidectomy was performed. On gross examination no nodules or tumefactions were palpable. Histopathology showed diffuse C-cell hyperplasia in the midst of which a C-cell tumor and micromedullary carcinoma of the thyroid were found. Morphologically the full spectrum of changes from focal C-cell hyperplasia through the stages of diffuse and nodular hyperplasia to the final development of medullary carcinoma are demonstrated by light and electron microscopy. The patient's postoperative course was benign and for the subsequent three years he had continued asymptomatic with normal calcitonin levels.