Surgery for parathyroid microadenomas: patient characteristics, localization success and operative cures

Primary Hyperparathyroidism: Outcomes of Repeated Imaging After Initial Negative Radiological Localization

BACKGROUND

Radiological localization imaging aids in the identification of abnormal parathyroid glands resulting in primary hyperparathyroidism (PHPT), thereby facilitating minimally invasive parathyroid surgery. Sometimes initial imaging may fail to identify the abnormal gland and imaging may therefore be repeated. This study explored patient outcomes of repeated parathyroid localization imaging, after initial negative gland localization, at a United Kingdom institution.

METHODOLOGY

Data was retrospectively collected and analyzed for patients with PHPT undergoing repeated imaging during a five-year period (2015-2020). The total number of episodes of scanning, types of scans performed, the time interval between scans and the imaging success of gland localization were recorded. We explored the reasons for repeated imaging and attempted to identify any factors that might predict subsequent positive radiological localization.

RESULTS

A total of 45 patients were identified who underwent repeated localizing imaging after first localizing imaging was negative. Of these, 39 did not undergo surgery despite repeat imaging being undertaken; 11 out of these 39 patients (28%) had subsequent positive localization scans. Again, a large proportion of patients were managed conservatively, despite the repeated sets of imaging being done. Patients undergoing three or four sets of repetitive imaging did not have imaging or surgical success.

CONCLUSION

A streamlined parathyroid pathway should be followed whereby patients should be triaged for suitability for surgery prior to repeated imaging. A second set of scans should be offered when patients are unsuitable for conservative management and are willing and fit to undergo surgery. There is no merit to repeating imaging more than twice.

Surgical challenges of giant parathyroid adenomas weighing 10 g or more

PURPOSE

An average parathyroid adenoma (PA) weighs < 1 g. This study aimed to characterise giant PAs ≥ 10 g (GPAs) to facilitate surgical management of primary hyperparathyroidism (PHPT).

METHODS

All patients with a GPA confirmed on histology were recruited from the Monash University Endocrine Surgery Unit database. Clinical and demographic data were collected and compared to a group of non-GPA patients.

RESULTS

A total of 14 GPAs were identified between 2007 and 2018 out of 863 patients (1.6%) with a single PA excised for PHPT. The GPA patients were compared to a control group of 849 non-GPA patients in the same period with similar mean age (62 ± 16 vs 63 ± 14, P = 0.66) and gender distribution (64% vs 75% female, P = 0.35). Pre-operative calcium (Ca) and parathyroid hormone (PTH) levels were significantly higher in GPA patients (P < 0.001). A higher percentage of GPA patients (79%) had concordant localisation studies (ultrasound and sestamibi) than control patients (59%), (P = 0.13), but they were significantly less likely to undergo MIP (55% vs 82%, P = 0.02). The median GPA weighed 12.5 g (IQR 10.5-24.3). Median serum Ca normalised by day 1 post-operatively, while PTH remained elevated. Both serum Ca and PTH levels were in the normal range at 3 months. All GPA lesions were benign on histopathology.

CONCLUSION

GPAs are rare and display severe clinical and biochemical abnormalities. Despite their large size, concordant pre-operative imaging was not always achieved, and a few patients were suitable for MIP.

Two-year changes of biochemical profiles and bone mineral density after percutaneous ultrasound-guided microwave ablation for primary hyperparathyroidism

PURPOSE

To investigate the changes of the serum parathyroid hormone (PTH) and calcium level, as well as bone mineral density (BMD), after percutaneous ultrasound-guided microwave ablation (MWA) for primary hyperparathyroidism (pHPT) caused by single hyperfunctional nodule.

METHODS

The study enrolled 20 patients with a total of 20 nodules of MWA treatment to pHPT in one session. The normalization rate of the serum PTH and calcium was evaluated at every 6 months during 2-year follow-up after MWA. The bone mineral density (BMD) at lumbar spine and femoral neck were also compared before and after the procedure.

RESULTS

The normalization rate of both PTH and serum calcium at 6-, 12-, 24-month follow-up was 66.6%, 80.0%, and 62.5%, respectively. Though the normalization rate of serum calcium level at 6-, 12-, and 24-month visit after MWA was 100%. The BMD increased 12, 24 months after MWA at lumbar spine (1.022 ± 0.155, 1.057 ± 0.151 vs 0.965 ± 0.145 g/cm², p < 0.01) and femoral neck at 2-year assessment (0.819 ± 0.094 vs 0.771 ± 0.102 g/cm², p = 0.015). Seven nodules disappeared in 20 nodules (35.0%), average ablation time was 122.29 ± 107.54 s (34-460 s). Six patients encountered voice change during the procedure, one participant was confirmed recurrent laryngeal injuries but recovered within 2 months.

CONCLUSIONS

Percutaneous ultrasound-guided microwave ablation results in improvement of biochemical profiles and bone mineral density in subjects with single hyperfunctional parathyroid nodule. However, the long-term efficacy of the MWA remains to be verified.