ACTA ENDOCRINOLOGICA (BUC)

A 62 years old woman was diagnosed with multinodular toxic goiter and primary hyperparathyroidism/ left parathyroid adenoma by hormonal assessment, ultrasound and nuclear thyroid/parathyroid scans. Cervical ultrasound illustrated a multinodular aspect of the thyroid with solid nodules and cystic-component nodules; the larger one represented a multinodular complex with necrosis areas in the left thyroid lobe, ACR TI-RADS score 4 (moderately suspicious). Functional nuclear imaging was performed for accurate differential diagnosis between thyroid vs. parathyroid localization, between cold vs. hot nodules, and eventually, for guiding the choice of a subsequent Fine- Needle Aspiration Biopsy (FNAB). Scans described an early intense 99mTc-sestaMIBI uptake with no 99mTc-pertechnetate uptake in the left thyroid lobe larger nodule. Due to the suspicion of malignancy for this nodule, we performed an additional scan (1 hour before the classical 2 hours parathyroid delayed scan). The intense uptake persists in both delayed scans suggesting no malignant phenotype and which was confirmed after surgery by benign histology. In conclusion, using a 99mTc-sestaMIBI personalized protocol, related to the radiotracer cellular uptake mechanisms: 1 hour scan (supplementary image, corresponding to the maximum uptake pattern of 99mTc-sestaMIBI for cancer cells) and 2 hours scan (for parathyroid washout evaluation) may avoid unnecessary extensive thyroid surgery.