ABSTRACT
BACKGROUND: Thyroid cancers with pulmonary metastases have been well documented. However, malignant pleural effusion has rarely been reported. CASE REPORT: We present a 77-year-old patient who had Hürthle cell carcinoma of the thyroid with contralateral malignant pleural effusion. The diagnosis was based on consistency in the histopathological and immunohistochemical features of pleural fluid cytology and the final pathology of the thyroid tumor. RESULTS: The patient was treated with total thyroidectomy and postoperative radioactive-iodine ablation. Unfortunately, he died for recurrent pleural effusion and pulmonary complication 6 months later. CONCLUSION: Identifying the origin of malignant pleural effusion is important to provide treatment guidance. In this report, we review the literature on diagnosis and treatment of thyroid cancer with malignant pleural effusion.