Mr. <PATIENT_NAME> had previously been diagnosed with a G3-differentiated basaloid HPV-16-positive squamous cell carcinoma on the left cervical side. During the initial operation, a suspicious finding was found in the area of the left upper tonsil pole. Pathohistologically, however, there was no evidence of a primary tumor. Therefore, initially suspected CUP syndrome and therefore further appropriate CUP diagnostics. The subsequent PET-CT showed no evidence of further metastases in addition to the metastatic conglomerate on the left side. Only a slight increase in the area of the left tonsil. There is now an indication for a left tonsillectomy and frozen section diagnostics. In addition, a modified radical neck dissection on the left side is indicated. Due to the sonomorphologic cN2b neck status and the unremarkable cervical PET findings on the right, a neck dissection on the right side does not appear to be indicated. The patient consented to the planned procedure.