Surgical treatment of metastasis to the thyroid gland: a single center experience and literature review.

BACKGROUND: Metastasis to the thyroid gland or nonthyroid malignancy (NTM) is rarely an indication for thyroidectomy and constitute 1-3 % of all thyroid carcinomas. NTM has a poor prognosis, due to the advanced stage of the primary tumor. This study aimed to present the incidence, clinical characteristics, and treatment outcome of NTM in a single, high volume center. CASE SERIES: We retrospectively analyzed all patients who had undergone thyroidectomy at the Center for Endocrine Surgery in Belgrade, during the period from 1995 to 2015. Out of 13,385 patients who were submitted to thyroidectomy, 3,344 (24.2 %) patients had thyroid malignancy. The diagnosis of NTM, based on the histopathological findings, was found in ten patients (0.075 % of all patients who had thyroid surgery, i.e., in 0.3 % of patients with thyroid cancer), with a mean age of 59.5 years. The most frequent primary tumor location in NTM was kidney in four patients, esophagus in two patients, and pharynx, breast and lungs (one case each). Total thyroidectomy was performed in four patients and lobectomy in two patients. Mean survival time following thyroid surgery was 43.2 months. CONCLUSION: NTM are uncommon, and their prognosis is generally poor and depends on the characteristics of the primary tumor. Nevertheless, in selected cases, surgical treatment of NTM should be considered. HIPPOKRATIA 2018, 22(3): 137-140.