Massive lateral neck mass: aberrant ectopic thyroid malignancy

Lateral aberrant ectopic thyroid is very rare, comprising only 1%-3% of all the ectopic thyroid tissue. Clinically, these lesions are mistaken for lymph node swelling or metastatic tumour. Primary carcinoma in lateral aberrant ectopic thyroid with normal active native thyroid is very uncommon. We report a case of papillary carcinoma in lateral aberrant ectopic thyroid tissue, with a completely normal native thyroid gland in a 53-year-old man, who presented with a massive swelling in the lateral aspect of the neck clinically and radiologically diagnosed as a malignant soft tissue tumour with differential diagnosis of malignant lymphoma. Fine needle aspiration cytology revealed metastatic papillary carcinoma. In toto excision of the soft tissue mass along with subtotal thyroidectomy was performed. Histology of the mass revealed papillary carcinoma of lateral aberrant ectopic thyroid, while the thyroid gland did not show evidence of malignancy. The postsurgical period was uneventful, and the patient underwent radioiodine ablation.