The patient was initially found to have a pN2c neck status without evidence of primaries in the case of pT2 tonsillar carcinoma in 2008. After exclusion of suspicious primary areas on PET-CT, CUP panendoscopy revealed a differentiated squamous cell carcinoma in a blind biopsy in the area of the left base of the tongue which could not be detected macroscopically despite multiple panendoscopies. Hence the indication for resection. In addition, the postoperative sonography and questionable PET-CT showed 3 suspicious changes supraclavicularly, therefore indication for neck revision.