Endocrine Abstracts

Introduction: Medullary thyroid carcinoma (MTC) is a rare neuro-endocrine tumor arising from the parafollicular cells of the thyroid gland. MTC produces calcitonin, and elevated calcitonin level is an essential feature of this tumor. MTC constitutes approximately 4% to 10% of all thyroid cancers. The objective of our study is to discuss the clinical aspects and therapeutic modalities of MTC through our series with review of the literature.

Patients and Methods: This is a retrospective study involving 11 cases of medullary thyroid carcinoma, collected over a period of 21 years (2001-2021).

Results: The mean age was 43 years (ranging from 36 to 90 years). The sex ratio was 4.5 (9 males/2 females). The average consultation delay was 5 months. The primary reason for consultation was an anterior basicervical swelling in 81.8% of cases, dysphonia in 9.1% of cases, and bone pain in 9.1% of cases. Physical examination revealed an anterior basicervical swelling in all cases. Cervical lymphadenopathy was found in 63.6% of cases. Thyrocalcitonin levels were assessed in two patient and were found to be elevated. Neck ultrasound, performed for all patients, revealed thyroid nodules classified as EU TIRADS IV in 36.4% of cases and EU TIRADS V in 63.6% of cases. The diagnosis was made after fine needle aspiration in 45.5% of cases. All our patients underwent total thyroidectomy with central neck dissection. Eight patients had bilateral functional neck dissection in six cases. A total laryngectomy was indicated in one case, due to tumor extension to the trachea and cricoid cartilage. Adjuvent radiotherapy was performed in 9 cases. The final histologic exam showed locoregional nodal metastasis in seven patients. Distant metastases were found in 4 cases (pulmonary, hepatic, osseous, and nodal). The follow-up was marked by the absence of recurrence in 7 patients, superior mediastinal nodal recurrence in one patient, death in one case. Two patients were lost to follow-up.

Discussion/conclusion: Seventy-five percent to eighty percent of MTCs are sporadic, and the remainder is familial as part of multiple endocrine neoplasias (MEN) 2A, MEN 2B, and familial medullary thyroid cancer. Prophylactic thyroidectomy is recommended for patients with mutations that put them at high risk. Various tyrosine kinase inhibitors are approved for use in progressive, metastatic medullary thyroid cancer. Finally, prognosis depends on the age of the patient, histologic grade, and status of surgical resection. The five-year survival for stages 1 to 3 is 93% compared to 28% for stage 4.