Ectopic thyroid tissue

Thyrotoxicosis factitia should be suspected in a thyrotoxic patient without evidence of increased hormone production, thyroidal inflammation, or ectopic thyroid tissue. The RAIU is low because thyroid gland function is suppressed by the exogenous thyroid hormone. Measurement of plasma thyroglobulin reveals the presence of very low levels. 

J. Ectopic thyroid tissue (struma ovarii, thyroid carcinoma metastases)... 

Thyroid stimulators other than TSH" Ectopic thyroid tissue... 

Fluorescent thyroid scanning A method based on stable iodine measurements. Mayo Clin Proc 53 151-156. McCormick MV, Wahner HW. 1978. Effect of background radiation change on measurements of iodine by x-ray fluorescence technique. J Nucl Med Technol 6 30-33. Sweet RA, Wahner HW. 1977. False-positive fluorescence thyroid scan for ectopic thyroid tissue. J Nucl Med 18 1142-1143. 

The investigation of children with thyroglossal cysts shows a definite useful clinical application of the fluorescent technique using either a scanner or a stationary system. These cysts may be confused with ectopic thyroids and misdiagnosis may lead to excision of the patient s only thyroid tissue and result in hypothyroidism. It is thus essential to establish that a normal thyroid is present before excising a suspected thyroglossal cyst. A radionuclide scan is usually advised but a fluorescent study either with a scanner or more simply with a... 

To study the relationship of dietary iodine intake and thyroid autoimmune phenomena further, various groups of Wistar rats were kept on either a normal, low (LID) or high (HID) iodine diet. The iodine deficient rats developed a mild infiltration in their thyroid glands of Th, Tc/s and dendritic cells. The dendritic cells formed clusters with each other. Moreover, a higher percentage of the iodine deficient rats had anti-colloid antibodies after 10 weeks of diet compared to the normal rats (80-90 % vs 40-50 % respectively). Wistar rats on a HID did not develop lymphoid cell infiltration, but unexpectedly ectopic thymic tissue in connection with the thyroid was seen and only a low percentage of these rats had anti-colloid antibodies after 12 weeks of diet compared to the control rats (15-25 % vs 40-50 % respectively). 

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