5 Key Takeaways

• 1

  A rare case of intrathyroidal parathyroid adenoma coexisting with papillary thyroid carcinoma was reported, highlighting diagnostic challenges.

• 2

  This case is the first documented instance of papillary thyroid carcinoma invading an intrathyroidal parathyroid adenoma.

• 3

  Intrathyroidal parathyroid adenomas account for less than 6% of primary hyperparathyroidism cases and can mimic benign thyroid nodules.

• 4

  Fine-needle aspiration biopsy may misidentify parathyroid adenomas as thyroid lesions, complicating preoperative diagnosis.

• 5

  Thorough histologic examination of thyroidectomy specimens is crucial, as parathyroid adenomas do not exclude concurrent thyroid malignancy.