Cystic lesions of the neck are frequently encountered on clinical basis. The usual differential diagnosis includes branchial cleft, cystic hygroma, dermoid cyst, tuberculous lymphadenitis, benign detached goiterous thyroid cyst, and Cavitation epidermoid carcinoma. Most of cysts are benign and malignant cysts are rare. The most common form of cystic malignancy in the lateral neck is cystic degeneration of epidermoid carcinoma metastatic to cervical lymph nodes. Cystic neoplasia may result from malingnant changes occurring within the wall of a previously benign cyst Complete head and neck examination on the primary focus is important Especially, when palpation of thyroid is negative, thyroid carcinoma is easily overlooked. Recently, we experienced papillary carcinoma of the thyroid seen as lateral neck cyst. So we report this case with review of literatures.