ANAPLASTIC THYROID CARCINOMA DEVELOPED YEARS AFTER THE PATIENT HAD UNDERGONE PARTIAL THYROIDECTOMY DUE TO PAPILLARY THYROID CARCINOMA.

Thyroid cancers are frequently seen tumors and surgery is the gold standard in treatment. An 80-year-old female patient presented to our department with right side neck swelling and shortness of breath. Her history revealed that she had undergone a near-total thyroidectomy 10 years before due to papillary thyroid carcinoma and she had a growing swelling in her neck in the last 2 years. A hard mass involving the whole right side of her neck was found on physical examination. Tomography showed a mass on the right side of the neck approximately 10x12 cm in size with heterogeneous density, which was pushing the trachea to the left. Fine needle aspiration biopsy findings suggested undifferentiated malignant tumor, i.e., anaplastic thyroid carcinoma were obtained while her distant organ scans were normal. The patient was operated under general anesthesia; she underwent completion total thyroidectomy and radical neck dissection. As a result of the histopathologic examination, she was diagnosed with anaplastic thyroid carcinoma. The patient received radioactive I-131 therapy and no problems were found at her 3-month follow up examination. In conclusion, when surgical near-total thyroidectomy is performed in patients with papillary thyroid carcinoma, a new malignancy may develop in the residual thyroid tissue even after many years. In such cases, completion total thyroidectomy and adjuvant multimodal treatment methods should be preferred.