PET Papillary Thyroid Cancer

Clinical History

This is a 76-year-old male with papillary thyroid cancer that had a thyroid ablation with 200mCi of ¹³¹I four years ago.

Technique

The patients blood glucose was 170mg/dl just prior to the time of injection. The patient was injected intravenously with 16.4mCi of ¹⁸F-FDG and forty-five minutes later, PET/CT images were acquired from the base of the brain to the mid thighs. Images were then reconstructed in the transaxial, sagittal and coronal planes and the PET and CT images were fused for anatomic comparison.

Findings

There is normal metabolic activity identified within the heart, liver, kidneys with excretion into the urinary bladder. Multiple abnormal areas of increased metabolic activity are identified scattered throughout the entire body. There is a focus of increased metabolic activity corresponding to a metastasis within the choroid plexus in the posterior horn of the left lateral ventricle. There is a focus of increased metabolic activity within a large metastasis in the left sphenoid wing and there is a focus of increased metabolic activity within the skull base adjacent to the left mastoid air cells in the left temporal bone. There are extensive foci of increased metabolic activity within multiple lymph nodes throughout the entire torso. There are small soft tissue pulmonary nodules within the left lower lobe, right lower lobe, and right upper lobe, which demonstrate no abnormally elevated metabolic activity but are too small to accurately characterize by PET and are suspicious for early pulmonary metastases.

Impressions

WIDELY METASTATIC INVOLVEMENT BY THE PATIENT'S KNOWN THYROID CANCER WITH EXTENSIVE SKELETAL AND LYMPH NODE METASTASES, AS WELL AS A BRAIN AND SKULL BASE METASTASES AS DESCRIBED. THERE ARE ALSO SEVERAL QUESTIONABLE SOFT TISSUE PULMONARY NODULES THAT ARE TOO SMALL TO ACCURATELY CHARACTERIZE BY PET, BUT ARE SUSPICIOUS FOR EARLY PULMONARY METASTASES.