Defection of distant medullary thyroid carcinoma metastases by Tc-99m arcitumomab scintigraphy

A 54-year-old woman with a history of medullary thyroid carcinoma after total thyroidectomy in 1992 was examined and found to have increasing serum carcinoembryonic antigen and calcitonin levels. Imaging with Tc-99m DMSA, neck and mediastinal MRI, and In-111 octreotide failed to reveal any recurrence or metastasis. Tc-99m arcitumomab scintigraphy showed increased uptake in the left lateral pelvis indicative of a metastatic focus. Follow-up pelvic MRI and whole-body bone scintigraphy revealed a correlative focal abnormality in the left anterior iliac bone. A CT-guided biopsy of this region revealed metastatic medullary thyroid carcinoma.