Primary branchiogenic carcinoma is a rare malignant tumor resulting from the malignant transformation of a branchial cleft cyst. In the case we describe, CT scanning and ultrasonography demonstrated the characteristic findings of a second branchial cleft cyst located in the anterior triangle of the neck, along the anterior margin of the sternocleidomastoid muscle. This lesion presented as a well-defined cystic mass with a thick irregular inner wall and central septa, and associated multiple neighboring necrotic lymph nodes. Microscopic examination revealed a transition zone from squamous epithelium to squamous cell carcinoma.