Widespread Skeletal Metastases in Medullary Thyroid Carcinoma

Key Points

• This case aims to illustrate the challenges in diagnosing skeletal metastases in medullary thyroid carcinoma (MTC).
• Documented case of a 78-year-old woman with MTC and elevated serum calcitonin.
• Used 99m Tc-octreotide imaging which failed to detect metastases.
• Employed 68 Ga-FAPI PET/CT which showed extensive skeletal involvement.
• Compared biochemical markers with disease burden.
• 99m Tc-octreotide imaging did not reveal skeletal metastases, despite elevated calcitonin levels.
• 68 Ga-FAPI PET/CT imaging identified significant skeletal metastases.
• Biochemical markers were low compared to the extent of the disease, indicating a low-secretory form of MTC.

Abstract