After problem-free intubation by the anesthesia colleagues, repeated pharyngoscopy and laryngoscopy with the Kleinsasser C-tube after insertion of a mouth guard with confirmation of the previous panendoscopy findings without evidence of a primary tumor. Now incisional biopsies of the base of the tongue on the right, middle and left and monopolar coagulation. Hemostasis. Then insertion of the Mc Ivor oral flap and initially tonsillectomy on the left in the typical manner after exposing the tonsil capsule, the upper pole. Using the dissection technique after caudal detachment of the tonsil, which is macroscopically inconspicuous, very small. Separation at the caudal pole with a clear border to the base of the tongue. Hydrogen swab insertion and removal without evidence of bleeding. Identical procedure with analogous findings on the right side. Previously, epipharyngoscopy was performed without evidence of a tumor and nasopharyngeal curettage and insertion and removal of swabs and hemostasis. After completion of the panendoscopy without any problems, head positioning to the left for the neck dissection on the right: After infiltration in the area of the planned skin incision with Ultracaine 2% with Suprarenin additive, skin disinfection/ablation and sterile draping. Marking of the landmarks and the curved neck incision cervically on the right at the front edge of the sternocleidomastoid muscle. Cut through the skin and subcutaneous tissue. Exposure and transection of the platysma. First preservation, then later ligation of the external jugular vein. Preservation and sparing of the auricularis magnus nerve. Dissection of the anterior edge of the muscle in depth and exposure of the accessorius nerve. Caudal exposure of the entire length of the omohyoid muscle, exposure of the belly of the submandibular gland and dissection along the capsule to the posterior digastric venter muscle. Insert the cranial and caudal retractors after dissection of all landmarks. Now first remove the anterior neck preparation down to the level of the superior thyroid artery after preparation on the internal jugular vein from caudal to cranial and mobilization of the neck preparations. Then clearing of the posterior neck preparation, starting at level IIb. Here, the conditions were heavily scarred due to the previous operation after the lymph node removal from level V far cranially. While sparing the accessorius nerve, which was also exposed during the previous operation, remove it down to the level of the scalene muscles. After clearing level IIb, continue resection of the neck preparation from cranial to caudal while sparing and preserving all plexus branches and the cervical nerve. Caudal resection below the level of the omohyoid muscle without evidence of chyle flow. Resection of the neck preparation behind the sternocleidomastoid muscle while sparing the plexus branches. This results in a neck dissection level II to V, with initial lymph node metastasis in level V. Macroscopically, this neck dissection shows enlarged lymph nodes up to approx. 1.5 cm in size, macroscopically also possible metastases, but not clear. Finally, hemostasis and completion of the procedure without complications after insertion and suturing of a Redon drainage and two-layer wound closure. Conclusion: CUP panendoscopy and neck dissection right level II to V in the case of a panendoscopy and lymph node extirpation from level V with histologically confirmed HPV-associated squamous cell carcinoma metastasis. Procedure: Redon ex depending on support, presentation at our tumor conference to discuss the tongue base biopsies, nasopharyngeal biopsy and tonsils on both sides as well as the neck preparation for planning adjuvant radiochemotherapy. Then also planning of a PEG insertion, for which the patient was not informed at the time of this operation.