Endocrine Abstracts

Introduction: Oncocytic (Hurthle cell) carcinoma is consisted of <5% of thyroid cancer but most metastasizing cancer type among differentiated thyroid cancer. We presented an oncocytic carcinoma with sternum metastasis.

Case: A 68-year-old women admitted to endocrinology policlinic with complaint of a mass in her neck. She was diagnosed hyperthyroidism and she was using thionamid for 6 months. Her medical history revealed hypertension for 3 years and asthma. In physical examination she had stage 3 guatr and fixed hard solid mass over sternum. In laboratory TSH and free T₄ was 0.06 μIU/ml (0.4–4.2 μIU/ml) and 07 ng/dl (0.8–2.7 ng/dl) respectively. In thyroid ultrasound in right thyroid lob the biggest nodule was 10 cm and in left lobe biggest nodule was 2 cm and thyroid gland was extending under sternum. Thyroid scintigraphy revealed hyperplastic thyroid gland with increased uptake and hypoactive nodules. In thorax CT there was a 5×5.5 cm mass on sternum that destructs the bone and invases to fat tissue of mediastinum. Thyroid fine-needle aspiration biopsy result was follicular neoplazm and biopsy of mass on sternum included atypical cells. Thyroglobulin washout was performed from mass on sternum and thyroglobulin level was >300 ng/ml. Bilateral total thyroidectomy and mass excision with partial sternum excision were performed by general surgery and thoracic surgery physicians. Postoperative thyroid pathology revealed well differentiated oncocytic carcinoma and pathologic result of sternum mass was metastasis of oncocytic carcinoma. Furthermore mediastinal and central lymph node metastasis detected. Radioiodine ablation performed to patients.

Discussion: Oncocytic cell carcinoma is considered a variant of follicular carcinoma. Metastasis is observed 34% of oncocytic carcinoma. Various studies reported that ‘oncocytic carcinoma’ is the most frequent cancer that metastasizes to bone. Even though oncocytic carcinoma has low radioactive iodin (RAI) uptake compared with follicular carcinoma, treatment of oncocytic carcinoma includes RAI ablation, so RAI ablation was performed to the patient. In light of this case we suggest scanning bone metastasis at the time of diagnosis among oncocytic carcinoma patients.