Endocrine practice : official journal of the American College of Endocrinology and the American Association of Clinical Endocrinologists 2017 11 16() doi 10.4158/EP-2017-0001
Although loco-regional metastases occur in 5-10% of patients with papillary thyroid cancer (PTC), distant metastases are rare, especially to the pancreas. Here we review the literature regarding metastases to the pancreas from PTC and present an illustrative patient.
The literature search was performed through www.pubmed.org . The information regarding our illustrative case was obtained from the medical records of our institution.
Since 1991, 11 cases of pancreas metastases of PTC have been reported. The average age at diagnosis was 55.3 years. There were 8 men and 3 women. Three had classic PTC histology; 2 had tall cell variant; and 2 had follicular variant. Four had T4 tumors, and 2 had T3 tumors. Seven had thyroid cancer spread to regional lymph nodes. One had distant metastasis. The pancreas metastasis was diagnosed from 1 month to 13 years after primary PTC was detected; average was 7 years. Our patient was an 84 year old woman diagnosed with PTC with a BRAFV600E mutation following total thyroidectomy. A whole body scan after radioactive iodine (RAI) remnant ablation was negative for metastases. A pancreatic tumor was identified 2 years later, on screening fluoro-deoxyglucose (FDG)-positron emission tomography (PET) scan. A biopsy of the tumor was histologically similar to PTC and positive for thyroglobulin, TTF-1, and the BRAFV600E mutation.
The biological reasons why PTCs metastasize to the pancreas have yet to be elucidated. Older patients with non-RAI avid, FDG-PET positive metastases and symptoms of pancreatitis are at increased risk of having this rare entity.