¹⁸Fluorocholine PET/CT in parathyroid carcinoma: a new tool for disease staging?

Excerpt

Parathyroid carcinoma is a rare neuroendocrine tumor, and there is no standardized diagnostic work-up for disease staging [1]. Because of promising results for 18 F-Choline PET/CT in the detection of parathyroid adenoma, we performed for the first time ¹⁸ F-choline PET/CT in a 53-year-old man treated for a parathyroid carcinoma with persistent postoperative elevated serum calcium and PTH [2, 3]. Whole body (WB) 99mTcMIBI scan (A), 99mTcHMDP bone scan (B) and 18FDG PET/CT (C) were also performed. The 18 F-choline (D) and 18FDG PET/CT detected pathological mediastinal lymphnodes and lung metastases. The 18 F-choline PET/CT detected one left soft tissue nodule in the neck (D; axial fused image, red arrow) and one cerebral frontal lesion confirmed to be local recurrence and brain metastases, both missed at 18FDG PET/CT. On the other hand 18 F-choline PET/CT missed one liver metastasis due to physiological liver uptake and two bone lesions located in the left pelvis detected by 18FDG PET/CT (C; fused axial image, white arrow) [4]. All lesions showed a very faint uptake on WB 99mTcMIBI scan. The 99mTcHMDP bone scan showed a diffuse cortical uptake in long bone typical of bone resorption but not any bone metastases. We demonstrated that distant metastases of parathyroid carcinoma showed high uptake of 18 F-choline and 18FDG and that the two techniques were complementary. The differences in FDG and choline uptake might be due to differences in tumor differentiation and proliferation, as it has been described in thyroid cancer [5]. ^{The 18} F-choline PET/CT should be considered in the future for parathyroid carcinoma work-up.

…