SAT-404 - Thyroid Gland Regrowth after Total Thyroidectomy

Background: Undergoing a total thyroidectomy usually assumes complete resection of all thyroid tissue, but regeneration in rare cases can occur. This is likely due to remaining embryological remnants including thyrothymic residue or pyramidal remnants (1).

Clinical

Case: A 58-year-old woman with a multinodular goiter involving nodules in the right and left thyroid lobes underwent FNA revealing a benign follicular nodule and a non-diagnostic sample, respectively. Although there were no signs of significant growth on follow up ultrasound imaging, the patient pursued surgical intervention due to difficulty swallowing, and underwent total thyroidectomy in 2013 with improvement reported. The patient later obtained a cervical spine MRI in early 2025 due to cervical radiculopathy, which revealed a partially visualized large left thyroid nodule measuring up to 3.9 cm. A thyroid ultrasound revealed a thyroid bed in the right and left neck with no focal fluid collection or sonographic adenopathy, and difficult imaging of the abnormality in the superior mediastinum with heterogeneous focus substernal measuring up to 5.9 x 5.6 x 5.5 cm. A neck CT with IV contrast revealed postsurgical changes of thyroidectomy and a 9 x 5 mm enhancing nodule in the left thyroidectomy bed that may represent residual thyroid tissue, residual/recurrent disease, or lymph node. A chest CT with IV contrast revealed markedly enlarged thyroid with superior extension, calcified nodules, and heterogeneous parenchyma. The patient underwent a hemi sternotomy with resection of the superior mediastinal mass, with pathology revealing benign thyroid parenchyma with nodular follicular hyperplasia and associated dystrophic calcifications and no malignancy identified.

Conclusions: This case demonstrates the possibility of thyroid tissue regrowth in a non-malignant manner after a presumed total thyroidectomy.

Reference: Snook, K.L., Stalberg, P.L.H., Sidhu, S.B., Sywak, M.S., Edhouse, P. and Delbridge, L. (2007), Recurrence after Total Thyroidectomy for Benign Multinodular Goiter. World J. Surg., 31: 593-598 36. https://doi.org/10.1007/s00268-006-0135-0

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