Endocrine Abstracts

Introduction: Parathyroid adenoma is the most common cause of primary hyperparathyroidism. Effective preoperative imaging and localizing the parathyroid adenoma is a prerequisite for the surgical treatment. 99mTc-MIBI scintigraphy in combination with ultrasound of the neck are the imaging modalities of choice before parathyroidectomy. However, both have limitations in terms of their efficacy in localizing the adenomas; ¹¹C-Methionine or 18F-Fluorocholine PET/CT has been reported to have utility in such cases.

Case report: We present a case of a 55-year-old woman with a long-lasting history of recurrent nephrolithiasis, and osteopenia, who was diagnosed with primary hyperparathyroidism. Two 99mTc-MIBI SPECT/CT scans were performed (2/2015 and 09/2015), and neither identified the parathyroid adenoma. ¹¹C-Methionine PET/CT was then performed (04/2016), and revealed the parathyroid adenoma as a focal (7×9 mm in size) uptake of the tracer behind the lower part of the right thyroid lobe.

Conclusions: ¹¹C-MET PET/CT has utility in preoperative localization of a parathyroid adenoma negative on 99mTc-MIBI scintigraphy in patients with primary hyperparathyroidism, and should be considered as a second-line imaging in such cases.

Keywords: primary hyperparathyroidism, ¹¹C-MET PET/CT, 99mTc-MIBI scintigraphy