Endocrine Abstracts

Introduction: Ectopic thyroid tissue is a rare developmental abnormality due to aberrant embryogenesis and/or migration of the thyroid gland. Although rare (<1%), papillary thyroid carcinoma is the most common malignant transformation.

Aim: Report a case of Tall cell variant of papillary carcinoma occurring on ectopic thyroid tissue in the thyroglossal duct.

Observation: A 56-year-old male patient consulted for a cervical mass appearing two years before, with progressive dysphonia. On physical examination, the patient had a firm tumefaction in the anterior cervical region, with undetermined limits, measuring approximately 7 cm. The thyroid gland was in the normal position. The thyroid function was normal. Neck ultrasound showed a heterogeneous hyperechoic left paramedian cervical mass with much vascularization on Doppler examination. No focal lesion in the thyroid gland was revealed. Cervical MRI provided a more precise assessment of the extension of the mass and confirmed the integrity of the other structures. The tumor was totally resected via a cervical approach. Histological examination confirmed its thyroidal nature, with the presence of tall cell variant of papillary carcinoma without capsular or vascular embolism. The treatment was completed by a total thyroidectomy and bilateral central lymph node dissection. The histological results were normal. The patient underwent radio-iodine therapy, 6 months after the surgery, with elevated initial thyroglobulin at 60 ng/ml. Later on, he developed lung and pleural metastases refractory to iodine. Thyroid suppression therapy was prescribed as an adjuvant treatment.

Conclusions: Although rare, papillary carcinoma on ectopic thyroid should be evoked before any mass of the hyoidal region. Its diagnosis is histological, only after surgical excision of the lesion. The treatment is primarily surgical associated with radioiodine I-131 therapy and suppressive hormone replacement therapy.