Hyperthyroidism with or without pyramidal lobe - Graves' disease or disseminated autonomously functioning thyroid tissue?

I-123 thyroid scintigrams performed in 349 patients were evaluated with a focus on specific thyroid gland vestiges, namely a pyramidal lobe or a thyroglossal duct. The detection of these vestiges in patients with hyperthyroidism is indicative of autoimmune hyperthyroidism. In Graves' disease, stimulating thyrotropin (TSH) receptor antibodies cause a significantly more frequent appearance of vestiges of the thyroglossal tract. In contrast, disseminated autonomously functioning thyroid nodules rarely show a pyramidal lobe. The frequency of pyramidal lobe visualization in patients with Graves' disease differed significantly from the frequency in patients with multifocal or disseminated autonomously functioning nodules. In euthyroidism patients, the vestiges may be indicative of the diagnosis of iodine deficiency with or without latent primary hypothyroidism. In thyroid scintigraphy, the pyramidal lobe and the thyroglossal duct can be visualized more easily using I-123 instead of Tc-99m sodium pertechnetate.