Accessing the influence of 99mTc-Sesta-MIBI-positive thyroid nodules on preoperative localisation studies in patients with primary hyperparathyroidism.

PURPOSE: Curative treatment for primary hyperparathyroidism (PHPT) is parathyroidectomy (PTX) with removal of the hyperfunctioning gland(s). In an endemic goitre region, 35-78% of PHPT patients show concomitant thyroid disease. This study aimed to evaluate if 99mTc-sestamibi (MIBI)-positive thyroid nodules decrease sensitivity in regard to localising the hyperfunctioning parathyroid gland(s) in PHPT patients.

METHODS

Within 5 years, 497 consecutive patients with biochemically proven PHPT were included in this study. The data was analysed retrospectively.

RESULTS

In total, 198 patients underwent PTX with thyroid surgery and 299 patients underwent sole PTX. Sensitivity of MIBI scan for PTX with and without thyroid surgery was 72.1% and 73.6%, respectively. A statistically significant difference in sensitivity of ultrasound for PTX with and without thyroid surgery (57.0% and 70.9%, respectively) was observed (p = 0.029). Thyroid nodule histology did not have a significant effect on the MIBI scan. Unilateral neck exploration (UNE) was performed in 110 patients and bilateral neck exploration (BNE) in 177 patients. The probability of surgical conversion from UNE to BNE due to incorrect localisation was 1.733 times higher in patients with thyroid nodules.

CONCLUSIONS

Concomitant benign thyroid nodules did not influence MIBI sensitivity. No correlation between thyroid carcinoma and MIBI uptake was determined. However, MIBI detection of thyroid malignancy is important in patients initially being considered for minimal invasive parathyroidectomy. Sensitivity and positive predictive value of ultrasound were significantly lower in patients with thyroid nodules. The probability of conversion from UNE to BNE due to incorrect localisation was 1.733 times higher in patients with thyroid nodules.