Thyroid hemiagenesis associated with Hurthle cell carcinoma: A case report

Introduction and importance: Thyroid hemiagenesis (TH) is a rare congenital anomaly where one lobe fails to develop, especially more frequently occurs on the left lobe. The exact mechanisms for thyroid morphogenesis remain unclear. In this paper, we report a rare case of right lobe TH associated with Hurthle cell carcinoma. Case presentation: A 59 years old woman was admitted with a neck lump increasing in size in the last 20 years. There were no symptoms of hyperthyroidism and hypothyroidism. There was a palpable, painless 5 cm mass in the middle of the neck. Initial thyroid ultrasonography (USG) revealed an enlarged left lobe, with hypoechoic lesion with cystic component and calcification (TIRADS 4). However, the right lobe was non-visualized. Fine needle aspiration biopsy result tendency was a malignancy. Hence, isthmolobectomy was conducted. Pathology result was Hurthle cell carcinoma. On the ninth month, USG revealed fibrotic tissue in the right thyroid bed and bilateral lymphadenopathy. Due to discrepancy, the patient was planned for a neck exploration surgery and a right lobe incision. Intraoperatively, the right thyroid was absent. Intraoperative USG also confirmed no right thyroid lobe. Discussion: Thyroid hemiagenesis can be visualized by using USG due to its practicality and cost effectiveness reasons. Follow up evaluations consisted of systematic monitoring of thyroid morphology and hormonal functions should follow the diagnosis of TH. Neck exploration surgery might need to be performed to clarify any discrepancy and confirm the diagnosis. Conclusion: TH can be recognized through supporting examination; however, discrepancy may occur.