Intrathyroidal Parathyroid Adenomas in Primary Hyperparathyroidism: Clinical and Imaging Findings

Area of Science:

• Endocrinology
• Surgical Oncology
• Radiology

Background:

• Primary hyperparathyroidism (PHPT) is a common endocrine disorder.
• Ectopic parathyroid adenomas can lead to persistent or recurrent disease after surgery.
• Intrathyroidal parathyroid adenoma (ITPA) is a rare cause of PHPT and ectopia.

Purpose of the Study:

• To investigate the clinical and imaging features of patients with ITPAs.
• To evaluate the effectiveness of radiological tools for ITPA localization.
• To assess surgical outcomes in patients with ITPAs.

Main Methods:

• Retrospective analysis of 708 parathyroidectomy cases for PHPT (January 2007 - December 2021).
• Inclusion of patients diagnosed with ITPA, excluding those with missing data.
• Review of clinicopathological features and radiological evaluation findings.

Main Results:

• 28 patients (3.9%) had ITPA, with 8 (1.1%) having complete intrathyroidal glands and 20 (2.8%) subcapsular glands.
• Ultrasound accurately localized ITPA in 89.3% of cases, while parathyroid scintigraphy succeeded in 64.3%.
• All patients underwent successful parathyroidectomy without persistence or recurrence.

Conclusions:

• ITPAs are uncommon in PHPT but can be accurately localized preoperatively.
• Ultrasound is a highly effective imaging modality for ITPA detection in experienced centers.
• Second-line imaging may be necessary for discordant or inconclusive scans, avoiding unnecessary thyroidectomies.