Objective  To investigate the strategy of diagnosis and surgery for intrathyroidal parathyroid lesions in patients with primary hyperparathyroidism.

  Methods  The clinical data of patients with primary hyperparathyroidism who had undergone parathyroidectomy between September 2003 and September 2012 in Peking Union Medical College Hospital were retrospectively analyzed for intrathyroidal parathyroid lesions.

  Results  Of 547 patients who had received surgical treatment due to primary hyperparathyroidism, 7(1.28%) were confirmed to be with intrathyroidal ectopic parathyroid by intraoperative exploration and postoperative pathology. Preoperative high-calcium crisis was noted in one of these seven cases. Ultrasound evaluation revealed lesion in thyroid in all seven patients before operations, and parathyroid was considered in five patients. ⁹⁹Tc^m methoxyisobutylisonitrile(⁹⁹Tc^m MIBI) single photon emission computed tomography (SPECT) was performed preoperatively in 6 patients, among whom 5 were found to be with abnormally hyperdense areas. Cervical computed tomography (CT) revealed intrathyroidal round-like lesions in 5 patients, although whether it was ectopic parathyroid could not be confirmed. Pathologic examinations of the resected lesions revealed adenoma (n=4), adenocacinoma (n=2), and hyperplasia (n=1). No relapse was noted after surgery. One patient who had repeatedly received three parathyroid surgeries developed mild hoarseness after the surgeries.

  Conclusions  Intrathyroidal parathyroid lesions in patients with primary hyperparathyroidism are rare conditions and therefore their preoperative diagnoses can be challenging. Multiple localization techniques should be employed to improve the surgical effectiveness and increase the accuracy of localization.