The Complementary Roles of 18F-Fluorocholine and 18F-Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography in an Evaluation of A Patient With Parathyroid Carcinoma: A Case Report.

¹⁸Fluorine-fluorocholine (¹⁸F-FCH) is a radiopharmaceutical used in primary hyperparathyroidism. The data about its utility in malignancies other than prostate and hepatocellular carcinoma is limited. We present the case of a patient who was referred for ¹⁸F-FCH positron emission tomography/computed tomography (PET/CT) due to the persistently elevated parathormone and calcium levels following total thyroidectomy with left lower parathyroidectomy for parathyroid carcinoma (PTC). Previously, the patient underwent ¹⁸Fluorine-fluorodeoxyglucose (¹⁸F-FDG) PET/CT. The latter method detected multiple mediastinal and hilar lymph nodes, as well as nodular lesions in lungs and osteolytic bone lesions with an increased tracer uptake, whereas ¹⁸F-FCH PET/CT detected an increased tracer uptake not only in lesions at all of the abovementioned areas, but also in the nodular lesion in the neck corresponding to a local relapse as well, with bone lesions showing higher avidity for ¹⁸F-FDG than for ¹⁸F-FCH. The case we present shows that ¹⁸F-FCH PET/CT has an additive value to ¹⁸F-FDG PET/CT in an evaluation of patients with PTC.