RESUMO
We report here on a rare case of papillary and follicular carcinoma of the thyroid gland that developed in a 31 years old woman who was previously diagnosed with Hashimoto's thyroiditis. Her chief complaint was a palpable neck mass. The antimicrosomal and antithyroglobulin antibody levels were elevated. Ultrasonography of the left thyroid gland revealed a 2.5x2.0 cm sized thyroid nodule. Fine needle aspiration biopsy of the thyroid nodule was done and this was diagnosed as Hashimoto's thyroiditis. There was no evidence of thyroid cancer. After 1 year, thyroid ultrasonography and biopsy were repeated for examining an enlarged thyroid nodule. Total thyroidectomy was then performed. The histopathologic examination revealed that the right and left thyroid glands were in accordance with the diagnosis of papillary and follicular cancer, respectively. Until now, no known case of simultaneous papillary and follicular carcinoma in Hashimoto's thyroiditis has been reported. This case suggests that adequate follow up for Hashimoto's thyroiditis patients with thyroid nodule may help the early detection and management of thyroid cancer.