Isolated Thyroid Metastasis of Malignant Melanoma with Unknown Primary Origin

Abstract
Clinically significant metastases to the thyroid gland are very rare; however, they can present as the initial malignancy. We report the case of a 70-year-old woman referred to our Endocrinology outpatient clinic for a thyroid nodule, which was in fact metastasis of malignant melanoma. Because fine-needle aspiration biopsy was not diagnostic and the nodule was considered malignant nodule according to the ultrasonographic examination, bilateral total thyroidectomy and modified radical neck dissection was performed. Histopathologic examination of the nodule was consistent with malignant melanoma. The message from this unusual case is that all thyroid nodules need to be taken seriously and a thyroid lesion may be the sentinel event in a patient with a malignant melanoma.