Outcomes of thyroidectomy for secondary thyroid malignancies, a single center experience

Metastasis of primary malignancies of other organs to the thyroid gland is a rare condition that may pose a diagnostic challenge. In this study, we aimed to report the clinicopathologic features and outcomes of patients treated for secondary thyroid malignancies in our center.

The results of patients who underwent thyroidectomy in our clinic between 2015 and 2023 were evaluated retrospectively. Four patients who met the inclusion criteria were evaluated.

The primary tumor was renal cell carcinoma in 2 patients and squamous cell carcinoma of the lung in 2 patients. Median age was 64 years (min:59-max:69). The median nodule diameter was 2.85 cm. Extrathyroidal spread was present in 1 patient with renal cell carcinoma metastasis. The other patient with renal cell carcinoma metastasis had lymphatic invasion. Vascular invasion was detected in 1 patient with renal cell carcinoma metastasis and 1 patient with squamous cell carcinoma of the lung metastasis. Surgical margin positivity was present in 1 patient in each group. The median overall survival time was 27 (min:10-max:44) months in the renal cell carcinoma group and 11 (min:6-max:16) months in the squamous cell carcinoma group. After the diagnosis of primary renal cell carcinoma, one patient metastasized to thyroid tissue 43.00 and one patient 94.00 months later. In the squamous cell carcinoma group, one patient showed metastasis to thyroid tissue 6.00 months after the primary diagnosis, while the other patient was first diagnosed with metastatic tissue.

Metastasis to the thyroid gland is a rare phenomenon with an incidence of 0.22% in all thyroid malignancies. It may occur before the detection of the primary tumor or during the follow-up of the primary malignancy. Although the overall prognosis is poor, it can be treated surgically.