68Ga DOTATATE PET/CT in Differentiated Thyroid Carcinoma With Fibular Metastasis and Mixed Response to Sorafenib

We describe somatostatin receptor targeted imaging findings in a 56-year-old woman with elevated serum thyroglobulin and radioiodine negative DTC fibular metastasis. The fibular lesion was biopsy proven of poorly differentiated thyroid carcinoma and demonstrated high grade uptake on Tc-HYNIC-TOC scintigraphy. She opted for sorafenib therapy for progressively increasing fibular swelling and was started on 400 mg daily followed by dose escalation to 400 mg twice daily. At 17 months after sorafenib initiation, Ga DOTATATE PET/CT demonstrated necrosis of the fibular lesion; however, new lesions were documented in lower dorsal and lumbar vertebrae and skull, based upon which sorafenib withdrawal was contemplated.