Synchronous Occurrence of Papillary Thyroid Carcinoma and Medullary Carcinoma in Hashimoto’s Thyroiditis and Multi Nodular Goiter Background

Background & Objective: Coexistence of follicular epithelial and bilateral parafollicular cells derivative of carcinomas in Hashimoto’s thyroiditis and multinodular goiter background are a very rare event. Of course, all benign and malignant thyroid lesions are more prevalent in iodine deficient areas. It seems that the context for identifying the pathways influencing thyroid carcinogenesis especially coincidence form has not yet been fully understood and needs further investigation. Here, we present a case with the synchronous occurrence of papillary thyroid carcinoma and medullary thyroid carcinoma in Hashimoto’s thyroiditis and multinodular goiter background.Case presentation: A ۵۴-year-old woman complained of a painless mass in the anterior region of the neck. The physical examination of the patient revealed multiple nodules in her thyroid gland. In ultrasound findings, she had thyroid enlargement associated with multiple isoechoic and hypoechoic nodules in both lobes. Thyroid fine needle aspiration results suggested the diagnosis of medullary thyroid carcinoma in Hashimoto’s thyroiditis and multinodular goiter background. The frozen sections, permanent sampling, and IHC examination showed the coexistence of papillary thyroid carcinoma with bilateral medullary thyroid carcinoma in Hashimoto's disease and multinodular goiter background.Conclusion: Studies debated about the risk factors of these pathologies including the same environmental issues or mutations in genomes and they emphasized surgeons should be aware of these lesions for diagnosis and interventional treatments. Following up the Hashimoto’s thyroiditis and multinodular goiter is required for detecting occult malignancies, and hence the right management and treatment should be performed.