Ectopic thyroid cancer with a normal thyroid gland

Abstract

Introduction: Ectopic thyroid tissue may appear in any location along the trajectory of the thyroglossal duct from the foramen cecum to the mediastinum, as either a lingual thyroid or a thyroglossal duct cyst. In rare cases, aberrant migration of the gland can result in lateral ectopic thyroid tissue. As for native thyroid gland, ectopic tissues are subject to malignant transformation. Case Report: A 40-year-old female patient presented with a right-sided neck swelling. She had a history of treated Hodgkin’s lymphoma at the age of 16 years. She has hypothyroidism and on thyroxine and is known to have benign small thyroid nodules for the last 7 years. The neck swelling was suspicious for papillary thyroid carcinoma upon cytological examination. She underwent surgery (total thyroidectomy with central and right lateral selective neck dissection) that confirmed the presence of papillary thyroid cancer in the neck but the thyroid gland was devoid of any cancer. The patient had post-operative radioiodine ablation. She is free of any recurrence or residual disease after one-year post-treatment. Conclusion: This case highlights the unusual presentation of thyroid carcinoma arising within an ectopic thyroid tissue in an otherwise cancer-free thyroid gland. The management of this case followed the standard treatment of metastatic thyroid cancer; however, it raises the question of whether these rare cases should receive de-escalation of standard management.