Frequency and characteristics of ectopic parathyroid adenomas in a cohort of patients referred for 18F-fluorocholine PET/CT

Abstract

Aim This article aimed to study the frequency and characteristics of ectopic/intrathyroidal parathyroid adenomas in patients referred for 18F-fluorocholine PET/computed tomography (CT). Patients and methods From 11 June 2015 to 15 January 2024, 729 patients were studied. Recorded patient variables included hyperparathyroidism type, sex, age, presence of symptoms, renal involvement, bone involvement, parathyroid hormone (PTH), and serum calcium, phosphate, and vitamin D as well as 24-h urine calcium excretion. PET/CT results were also collected. In case of parathyroidectomy, the weight of the adenomas was recorded. Continuous variables were expressed as mean ± SD. Differences were evaluated with Mann–Whitney U-tests or two-sample t-tests, when appropriate. P-values ≤0.05 were considered statistically significant. Results PET/CT showed no adenoma in 163 (22%), adenoma in 451 (62%), hyperplasia/multiglandular disease in 32 (4%), and equivocal results in 83 (11%) patients. A total of 6/729 (1%) adenomas were located intrathyroidally and 16/729 (2%) had an ectopic location. Patients with ectopic/intrathyroidal adenoma showed significantly higher serum PTH levels than patients with no visualization of adenoma on PET. The mean mass of the adenoma was 1 ± 2.3 g in patients with orthotopic adenomas versus 2.7 ± 3.3 g in patients with ectopic/intrathyroidal adenomas; however, this was not significantly different (P = 0.09). Conclusion In the presented cohort, the frequency of ectopic/intrathyroidal parathyroid adenomas was 3%. No significant difference in weight was found between orthotopic and ectopic/intrathyroidal parathyroid adenomas.