Large Remnant Ablation in the Treatment of Metastatic Papillary Thyroid Carcinoma: Case Report and Literature Review

Abstract

Objective: To report a case of large remnant ablation in a patient with metastatic papillary thyroid carcinoma. Methods: We present the initial presentation, radiologic findings and subsequent surgical and medical management. The pertinent literature and management options are also reviewed. Results: A previously healthy 80 year old woman presented to clinic with a large right-sided neck mass of several years duration. Fine needle aspiration biopsy was consistent with papillary thyroid carcinoma. Pre-operative CT imaging noted a 6cm by 6cm mass, extending into the mediastinum with mediastinal lymphadenopathy and numerous bilateral pulmonary nodules. She underwent tumor resection, however the left thyroid was left in place because the tumor extended retrosternally, and no plane could be established between the tumor and the larynx. She received 31.9 mCi of I-131 for ablation of the remaining left thyroid lobe four months later. Repeat CT imaging four months after the initial dose of I-131 showed regression of the mediastinal lymphadenopathy and pulmonary nodules, with the exception of one nodule in the right lower lobe. Approximately nine months after receiving the initial dose of I-131, she received 158.5 mCi I-131 for remnant ablation. CT imaging six months following I-131 remnant ablation noted interval increase in size of the nodule in the right lower lobe of her lung, but was otherwise unchanged from her previous CT. Conclusion: This case illustrates the use of radioactive iodine for ablation of a large thyroid remnant when total thyroidectomy is not an option in the management of metastatic papillary thyroid carcinoma.