Endocrine Abstracts

Introduction: Primary mucinous carcinoma of the thyroid gland is extremely rare. To the best of our knowledge, only nine cases have been reported in the literature. Our aim is to report a case of primary mucinous carcinoma of the thyroid gland and to describe its diagnostic and prognostic features.

Case Report: A 55-year-old man referred to our department for a 2-month history of an anterior neck mass associated with dysphagia. Physical exam showed a 4-cm and hard, right anterior neck mass, with left cervical lymph nodes (group V). Ultrasonography identified a 3-cm right thyroid nodule: EUTIRADS 5 with bilateral suspicious cervical lymph nodes. CT scan revealed a 3-cm hypodense right thyroid nodule associated with several mediastinal and cervical lymph nodes. TSH level was normal. Fine-needle aspiration (FNA) result was “nondiagnostic.” The patient underwent total thyroidectomy with bilateral central (group VI) and lateral neck dissections (groups II, III and IV). The tumour invaded the strap muscles and the left thyroid lobe. Several lymph nodes were noted in the central group, lateral cervical and mediastinal regions. Intraoperative examination was in favour of a poorly differentiated thyroid carcinoma. Postoperative course was uneventful. The histologic exam (with immunohistochemical study) confirmed the diagnosis of a primitive mucinous carcinoma of the thyroid gland. Surgical margins were positive. Lymph node metastases were noted in the central and lateral neck regions. The patient died 15 days after the surgery.

Conclusion: Primary mucinous carcinoma of the thyroid gland is unusual. Differential diagnosis must be discussed with other primary typical thyroid carcinomas or adenomas, metastatic carcinoma of the lung, breast, colon and other organs. Primary mucinous carcinoma has a worse prognosis than common thyroid carcinomas: survival ranging from 1 month to 2 years.