Papillary thyroid carcinoma in one of identical twin patients with Pendred syndrome

Pendred syndrome is an autosomal recessive disorder characterized by sensorineural deafness, a partial defect in iodide organification, and dyshormonogenetic goiter. Several cases of Pendred syndrome with follicular thyroid carcinomas were reported previously. Here we report identical twin patients with Pendred syndrome, who had thyroid tumors with distinct histopathological findings. 34-year-old identical twins with congenital deafness and goiter were referred to our hospital with complaint of neck discomfort. The genetic testing showed that these twin patients were compound heterozygotes carrying the same two mutations in the Pendred's syndrome (PDS / SLC26A4) gene (c2168A>G and ins2110GCTGG), which confirmed the diagnoses of Pendred syndrome. They underwent thyroidectomy. Histological examination of the thyroid tumors resected from these twin patients revealed follicular variant of papillary thyroid carcinoma, and diffuse and nodular goiter without any evidence of malignancy, respectively. To our knowledge, the former is the first case of follicular variant of papillary thyroid carcinoma in Pendred Syndrome.