Abstract: Papillary thyroid carcinoma (PTC) is the most common subtype of primary thyroid cancer.We herein present a case of predominantly cystic giant PTC coexisting with Hashimoto thyroiditis (HT).The multilocular cystic architecture and dense inflammatory infiltrate prompted us to conside r whether HT might represent a predisposing factor for PTC.The tumor was bulky and had invaded adjacent nerves;after palliative resection,the patient received adjuvant targeted therapy.The clinical course was complicated and the therapeutic benefit lim ited.

Key words: papillary thyroid carcinoma； hashimoto’ thyroiditis； cystic； treatment