IMPE Abstracts

Medullary thyroid carcinoma (MTC) accounts 5% of thyroid malignancies. Sporadic is in approximately 80% and hereditary in 20% of cases. When hereditary it can be associated with other benign endocrine neoplasia’s and/or typical no endocrine diseases, thus configuring the multiple endocrine neoplasia syndromes. Traditional therapies for advanced or metastatic progressive MTC (pMTC) are poorly effective so Tyrosine-kinase inhibitors (TKIs) therapy in children with MTC have reported partial responses in patients with unresectable locally advanced or metastatic disease. Vandetanib is an oral tyrosine kinase inhibitor that is approved by the Food and Drug Administration for the treatment of adults and children with locally recurrent or metastatic, progressive, of MTC.

Aim: To report a case of boy with Sporadic MTC treated with TKIs to prevent the progression of his disease.

Case report: A 9-year-old boy who had recurrent cough, dysphonia and progressive dyspnea. At physical examination was found a large tumor in the neck with regional adenopathy. Under fibroscopy we observed recurrent nerve paralysis and displacement of the airway. Laboratory test showed, Calcitonin: 3093pg/ml, CEA: 86.3ng/dl suggestive of MTC. Thyroid Ultrasound (US) showed enlargement left thyroid lobe with heterogeneous structure with hypoechoic predominance and micro calcifications with s peripheral vascularization. CT neck and chest: with signs of thyroid compromise and signs of expansion and compression of the airways and vessels with lung involvement in both bases and left upper lobe. With a presumptive diagnosis of MTC with pulmonary metastases and extensive local invasion thyroidectomy was performed with lymph node dissection of the level VI and partially left level II III. Cytopathology confirmed MTC multifocal variant with pT3: Molecular study of the RET proto-oncogene reported a sequence variation benign homozygous in exon 13, Leu769Leu. He started treatment with Levothyroxine. Due to the presence of an unresectable tumor the compassionate use of Vandetanib was indicated, showing a favorable clinical response without adverse events. Evolution under treatment during first year was optimal. We observed a decrease of 50% of the baseline levels of Calcitonin in a first 6 months and CT neck and chest with lung metastasis disappeared. The adjustment of levothyroxine dose might was needed during the first period of TKIs therapy.

Conclusion: MTC is not a frequent type of tumor in pediatric population. Calcitonin and CEA were useful markers to the rate of MTC. The use of Vandetanib should be considered in children and adolescents cases with great local and distant metastasis.