We report herein a rare case of massive pleural effusion caused by papillary thyroid cancer, which was accompanied by multiple pulmonary metastasis. A 91-year-old male patient presented with shortness of breath due to massive right pleural fluid. Cytological specimens, which were obtained from pleural fluid by thoracentesis, and was consistent with that observed in surgically resected thyroid cancer 6-year previously. Immunocytochemical staining of the cells was positive for cytokeratin (CK)-7, CK-19, and positive for thyroglobulin. Massive pleural fluid due to a metastatic from papillary thyroid cancer is very rare but may develop in long-term survivors with this disease as observed in this case.
Keywords: pleural effusion; thyroid cancer.