A 66-year-old man presented with the complaint of dyspnea. At the first medical examination, he was found to have cardiac tamponade, which was relieved by pericardiocentesis. Examination of the pericardial fluid revealed malignant cells, and the findings of PET-CT suggested pulmonary metastases from a thyroid cancer. We performed right thyroid lobectomy and histopathological examination revealed histological findings consistent with papillary adenocarcinoma in the form of lymphangiosis carcinomatosa. The patient was then diagnosed as having lung cancer with metastasis to the thyroid gland and cardiac tamponade due to malignant pericarditis. He received chemotherapy for extensive-stage small-cell lung cancer. One year after the surgery, the tumor size of the lung remains small and there is no evidence of any recurrence of cardiac tamponade.
Development of a thyroid metastasis or cardiac tamponade due to malignant pericarditis would seem to represent the terminal stage of lung carcinoma, however, prompt diagnosis and appropriate treatment sometimes improve the prognosis of the patient.
