Solitary liver metastasis from follicular variant papillary thyroid carcinoma: A case report and literature review

INTRODUCTION: Papillary (PTC) and follicular (FTC) thyroid carcinomas, together known as differentiated thyroid carcinomas (DTC), are among the most curable of cancers. Sites of metastases from FTC are usually osseous and those from PTC are in regional nodal basins and the lungs. Visceral metastases are rare and when they do occur, they tend do so in multiple sites. We present the case of a patient with a follicular variant of PTC and a solitary metastasis to the liver then review the relevant literature. PRESENTATION OF CASE: An otherwise healthy 68-year-old woman was diagnosed with follicular variant papillary thyroid cancer in 2003 and subsequently underwent thyroidectomy. The patient’s endocrinologist conducted surveillance of her thyroid cancer. In 2012, due to rise in thyroglobulin, a whole body radioiodine scan was obtained which revealed an iodine-avid left liver lobe mass. Three cycles of radioiodine ablation therapy were unsuccessful and eventually the patient was referred for surgical resection. Metastatic evaluation including a PET scan was negative with the exception of an isolated enhancing 4 cm mass in segment 4B of the liver. Anatomic segmental resection of liver was performed without complications. Intraoperative ultrasonography was used to guide resection of the liver mass. Pathology reports confirmed metastatic follicular variant of PTC. Surgical margins were free of tumor. Patient was discharged home and is doing well one year after surgery. The latest thyroglobulin level was undetectable. DISCUSSION: Post-operative surveillance by PCP, endocrinologist or surgeon for patients with thyroid carcinoma should be performed routinely. If identified, a solitary liver metastasis from primary thyroid carcinoma should be considered for surgical resection. Due to sparse data available in literature, collecting more data to establish algorithms for treatment of such rare metastatic cancers may be able to aid physicians to achieve better outcomes. CONCLUSION: Rare distant sites of metastases from DTC include eyes, pharynx, skin, muscle, ovaries, adrenal glands, kidneys, esophagus, pancreas and liver. Isolated, resectable liver metastases from PTC are exceedingly rare. Literature review revealed only 10 reported cases of liver metastases from DTC. As in our patient, solitary liver metastasis from PTC should be considered for surgical resection which offers the best chance for prolonged survival.