18F-Fluorocholine PET/CT in the Detection of Hyperfunctioning Transplanted Parathyroid Tissue.

A 54-year-old woman diagnosed with multiple endocrine neoplasia syndrome type 1 and primary hyperparathyroidism underwent total parathyroidectomy with autotransplantation of parathyroid tissue fragments in the right forearm in 1999. Since several years later, follow-up laboratory examinations showed the relapse of hypercalcemia; the patient started cinacalcet therapy. To exclude the presence of hyperfunctioning parathyroid glands in ortotopic or ectopic sites, a PET/CT scan with 18F-fluorocholine was performed. The PET/CT scan excluded the presence of ortotopic and ectopic parathyroid glands but showed a hyperplastic parathyroid fragment in the right forearm, responsible for the patient's persistent hypercalcemia.