Do Pyramidal Lobe Remnants After Thyroidectomy Influence Thyroglobulin and TSH Levels?
Posted: Monday, April 5, 2021
A study conducted by Erman Cakal, MD, of Diskapi Yildirim Beyazit Training and Research Hospital, Ankara, Turkey, and colleagues investigated the effect of pyramidal lobe remnants after total thyroidectomy on stimulated thyroglobulin. Published in Endocrine Practice, their research discovered increased stimulated thyroglobulin and decreased endogenous stimulated thyroid-stimulating hormone (TSH) levels in patients with pyramidal lobe residue. Consequently, the investigators indicated the need to consider such a complication in the follow-up of patients with differentiated thyroid cancer.
This study analyzed clinical data on 1,740 patients with differentiated thyroid cancer from the thyroid cancer database within the Department of Endocrinology and Metabolism of the investigators’ institution. The database was also utilized to identify patients with residual pyramidal lobe after total thyroidectomy. Images from postoperative technetium-99m pertechnetate thyroid scintigraphy were reevaluated to uncover any remaining residue. TSH and serum-stimulated thyroglobulin levels were measured within 6 months after total surgery.
In 10.4% of individuals who underwent total thyroidectomy, pyramidal lobe remnants were detected; in 1.6% of cases, ultrasonography displayed the pyramidal lobe's presence. In participants with and without such remnants, the median unstimulated thyroglobulin levels were 1.39 ng/mL and 0.55 ng/mL, respectively. As for unstimulated TSH levels, patients with pyramidal lobe residue had a higher median level than those without (10.6 mIU/L vs. 5.9 mIU/L). In patients with residual lobe remnants, the stimulated thyroglobulin levels were significantly higher than those without (1.99 ng/mL vs. 1.42 ng/mL). The endogenous stimulated TSH level for patients with such residue was 88 mIU/L, whereas individuals without such residue were 100 mIU/L.
A TSH level of at least 30 mIU/L—the level required for the maximum uptake of radioiodine—was not reached in 5.7% of patients with pyramidal lobe remnants and 2.3% of individuals without. There was no significant difference between patients with and without pyramidal lobes or remnants in regard to antithyroglobulin.
Disclosure: The study authors reported no conflicts of interest.