Thyroid Cancer Case 02

Clinical History
69-year-old male with thyroid carcinoma was treated with near total thyroidectomy followed by radioiodine ablation. During routine follow-up his serum thyroglobulin levels were found to be elevated. The radioiodine scan was negative. In view of the strong suspicion of metastases the patient was referred to PET/CT study for restaging.

Imaging Findings
STATED REASON FOR REQUEST: Restaging thyroid cancer
TECHNIQUE*: The whole body PET/CT study was performed approximately 90 minutes after intravenous administration of radiopharmaceutical.

PET/CT FINDINGS: The PET images showed hypermetabolic metastases in the enlarged left retropharyngeal and superior deep cervical lymph nodes. In addition two small nodal metastases with faint radiopharmaceutical uptake were visualized above and medial to the enlarged level 2 cervical lymph node lesion. They were clearly differentiated from the adjacent large cervical lymph node.

Another small focus of low uptake was visualized in the mediastinum.

Small metastasis in mediastinum

PET/CT FINDINGS (cont.): The fused images clearly delineated the small 4 mm metastatic lesion in the periesophageal region marked by the red arrow. A small 8 mm deep cervical lymph node metastasis was also well delineated above and separate from the large cervical nodal metastasis. The small focal area of radiopharmaceutical uptake in the mediastinum was localized to the posterior margin of the esophagus at the level of T8 vertebral body and appeared to be inflammatory in nature.

Defining recurrence and localizing very small metastases is critical to aggressive management of thyroid cancer. In this particular case, the PET/CT whole body images aided the physician in delineating small 4 mm neck lesions and revealed the true extent of disease so that the most appropriate treatment could be initiated.

Data courtesy of University of Tennessee Medical Center, Knoxville, Tennessee, USA

* Any of the protocols presented herein are for informational purposes and are not meant to substitute for clinician judgment in how best to use any medical devices. It is the clinician that makes all