[A case of micro-metastatic lung adenocarcinoma into adenoma of the thyroid].

In a case of 46-year-old woman, small nodules appeared in the anterior neck which was diagnosed as follicular adenoma of the left lower lobe of the thyroid. Four months before, she experienced resection of the lung and three courses chemotherapy of MVP for stage IIIb well-differentiated lung adenocarcinoma. Pathologically, micro-metastatic lung adenocarcinoma was found in the adenoma. It is very rare occurrence for lung carcinoma to metastasize into adenoma of the thyroid. But when tumors of the anterior neck are found in a patient of lung carcinoma, thyroid tumor must be considered for differential diagnosis.