The patient has a condition after neck dissection on the left side and CUP panendoscopy <2017>, with cervical left-sided CUP syndrome. The patient did not undergo adjuvant radiochemotherapy. The follow-up examination revealed a contrast-enhancing mass at the base of the tongue on the left side. A bipsie was taken by panendoscopy and a p16-negative squamous cell carcinoma was diagnosed. There is now an indication for transoral tumor resection. The patient was informed in detail preoperatively and had sufficient time to ask questions.