Endocrine Abstracts

Introduction: Thyroid nodules are common and are often found incidentally by palpation. Most of thyroid nodules are benign but 0–10% are malignant. A small proportion are due to metastatic lesions from other primary tumors. FNA is a standard diagnostic procedure to differentiate between benign and malignant nodules. But the use of additional immunochemistry markers will be important for diagnosis.

Lung adenocarcinoma is one of the tumors which may metastasize to the thyroid gland. We will present the case of a man who presented with neck enlargement and was subsequently diagnosed with metastases due to lung adenocarcinoma.

Case report: An 63-year-old man was referred to us for the neck enlargement.He had thyroid enlargement of the right lobe. Ultrasound revealed the solid hypoechoechoic mass and the afunctional nodule in the scintigraphy of thyroid.

After the fine needle aspiration cytology a primary thyroid carcinoma was suspected.

The whole body scintigraphy with Tc MDP shows the small photopenic zone in the body of 12th thoracic vertebra. The CT of thorax reveled a small pulmonary nodule.

The patient was suspected on a carcinoma of thyroid gland and was referred for total thyroidectomia.

The histopathology after total thyroidectomia based on the immunohistochemistry results, in one of the slides a small focus of a moderately to poorly differentiated adenocarcinoma was found. Tumor focus shows a negative reaction for TTF1, chromogranine and P53. But the tumor was positive for CEA and reveals a doubtful reaction for thyreoglobulin.

The thyroid tumor was diagnosed as metastases to the thyroid from lung adenocarcinoma.

Conclusion: This case shows the need of considering even rare possibilities in the differential diagnosis of thyroid nodule. Also the importance of immunohistochemistry markers.