Malignant Primary Paraganglioma of the Thyroid Gland: The First Reported Case

ABSTRACT Objective: Primary paragangliomas of the thyroid gland are rare tumors with just 45 previously reported cases in the literature. While locally aggressive tumor behavior has been documented, there are no reported cases of a malignant thyroid paraganglioma. Methods: This report presents the case of a 73-year-old female who presented with a rapidly enlarging right thyroid mass. Results: At the time of initial resection, the mass had grossly invaded the trachea and esophagus and encased the recurrent laryngeal nerve. Central neck lymph node metastases were present. A right thyroid lobectomy with central neck dissection was performed, with a final histologic diagnosis of primary paraganglioma of the thyroid gland. Within 1 year, the patient showed local tumor recurrence that required a laryngeopharyngectomy with reconstruction. New cervical lymph node metastases had also developed, and within 1 year a solitary liver metastasis was identified and excised, confirming the malignant nature of the tumor. Conclusion: Thyroid paragangliomas are an extremely rare subset of thyroid tumors that have gained increasing recognition as a clinical entity in recent years. Recent case reports and a review of the literature emphasize that despite a tendency to display aggressive local behavior; distant metastatic spread was not reported for any of the 45 previously reported cases. This is the first case to show clearly malignant behavior in a thyroid primary paraganglioma with local recurrence as well as regional lymph node and distant tumor metastases. This case has important implications pertaining to patient postoperative management and emphasizes the importance of perioperative and postoperative surveillance for possible local recurrence or metastasis.