Endocrine Abstracts

Background: Concomitant thyroid cancer in patients with congenital thyroid dyshormonogesis (TD) is extremely rare and only few cases of differentiated thyroid cancer in patients with TD were reported in literature. We present the first case of anaplastic thyroid cancer (ATC) in woman with TD.

Case: A 46-year-old female patient was referred to our hospital for thyroid surgery due to rapid tumor growing and compressive symptoms. The fine needle aspiration result of a local clinic was follicular neoplasm. She and her two younger sisters had diagnosed as congenital hypothyroidism and received thyroid hormone replacement therapy from childhood. The growth and psychomotor development of three sisters were within normal range. Her serum thyroglobulin (TG) level was not detected and genetic tests for TD were performed for patient and her younger sisters. The targeted exome sequencing revealed compound heterozygous mutations in the TG gene and saner sequencing represented a c.3790T > : C (P, Cys1264Arg) mutation located at exon 17 and c.7070T > : C (P. Leu2357Pro) mutation at exon 19 in patient and one sister. The c.7070T > : C (P.Leu2357Pro) mutation is novel mutation. After total thyroidectomy, she was diagnosed with ATC with lung and bone metastasis. She started Lenvatinib therapy and still alive for 11months after the first diagnosis of ATC.

Conclusion: TD patients are exposed to long term hypothyroid statuswith elevated thyroid stimulating hormone, which make thyroid goiter and nodules. Genetic mutation under chronic stimulation of the thyroid gland could change nodules to aggressive natures. Further investigation is necessary to identify the association between thyroid cancer and TD.