Initially, the operation begins with tracheoscopy: here, the glottic plane can be adjusted by laryngoscopy without any problems. Then inspection of the subglottis and the trachea up to the bifurcation with the O° optics. The mucosal conditions here are normal and inconspicuous. The patient is then intubated by the surgeon. Then oesophagoscopy: problem-free entry into the oesophagus with the flexible instrument. Then visual endoscopy into the stomach. A regular folded relief can be seen here. No evidence of a tumor or other mass. When reflecting back, careful inspection of the esophageal mucosa again, where irritation-free mucosal conditions can also be seen here, without any evidence of tumor growth. The patient is then repositioned and the hypopharynx and larynx are inspected again. Here too, the mucosal conditions were normal and completely unremarkable. The laryngeal skeleton is inconspicuous with non-irritated mucous membranes. The glottic plane is clear. The interary region and postcricoid region also appear completely normal. Then inspection of the oropharynx. Here, too, the mucosal conditions are largely normal and unremarkable. However, the left tonsil is slightly larger than the right and indurated. Other mucosal conditions in the area of the base of the tongue, the vallecula and the oral cavity are unremarkable. Due to the suspicious accumulation in the PET in the area of the tonsil and base of the tongue on the left side, the decision was made to perform a tonsillectomy, which was carried out without any problems. The specimen is then sent for frozen section evaluation. However, this is assessed as tumor-free in the frozen section. The decision was therefore made to perform a tonsillectomy on the right side. This was also carried out without any problems, sparing the anterior and posterior palatal arch, as on the left side. Subsequently, deep biopsies are taken from the area at the base of the tongue in the middle and on both sides. These are also sent separately for histological examination. Careful hemostasis is then performed. After re-inspection of the tonsilloliths with dry wounds, insertion of the velotractio and inspection of the nasopharynx. Here too, the mucosal conditions are normal and inconspicuous. Nevertheless, the nasopharyngeal curettage is performed here while sparing the tubal bulges. The removed tissue is also sent for histological examination. After careful hemostasis, the patient is repositioned for neck dissection on the right side. Injection of local anesthetic with adrenaline in the area of the old scar and along the front edge of the sternocleidomastoid muscle. After disinfection of the surgical field, skin incision along the anterior edge of the sternocleidomastoid muscle, including the old scar. Subsequent layer-by-layer dissection in depth. Exposure of the cervical vascular sheath. In the caudal area this appears completely inconspicuous. Exposure of the omohyoid muscle with exposure of the cervical vascular sheath. Then begin dissection of the caudal neck preparation where several hardened and enlarged lymph nodes can be palpated. These are all removed. Then dissection of the lateral neck preparation in a cranial direction. Several metastases can now be seen in the area of the vein angle, which appear to infiltrate the vein cranial to the vein angle. Now follow the exit of the facial vein proximally and visualize the capsule of the submandibular gland and the digaster muscle. This is then followed further dorsally. Find the hypoglossal nerve here. It can now be seen that there is a pronounced metastatic conglomerate in the area of the accessorius triangle at the transition to the hypoglossal triangle. The sternocleidomastoid muscle and accessorius nerve are deeply infiltrated by the conglomerate in this area. Now consult <CLINICIAN_NAME>, who recommends aiming for a radical approach here. Therefore, removal of the sternocleidomastoid muscle and the accessorius nerve. Dissection of the internal jugular vein. Subsequent dissection along the cervical vascular sheath in a cranial direction. In doing so, protect larger branches of the external carotid artery. The hypoglossal nerve as well as the vagus nerve and the border cord can also be spared. Then further dissection on the deep cervical fascia in a cranial direction. Here, several cervical plexus branches are also infiltrated by the conglomerate and must therefore also be resected. ............ Improvement of the overview. Then widen the skin incision retroauricularly. Expose the caudal pole of the parotid gland. Then remove the insertion of the sternocleidomastoid muscle at the tip of the mastoid. Also expose the posterior venter of the digaster muscle. The entire conglomerate can then be dissected cranially along the deep cervical fascia. In the vicinity of the skull base, the conglomerate must then be sharply dissected away from the vagus nerve and hypoglossus. Separate the proximal part of the internal jugular vein directly below the base of the skull. Then remove the entire conglomerate. Macroscopically, the resection appears healthy. Consult <CLINICIAN_NAME> again, who recommends that tissue samples be taken from the area of the sharp edges of the hypoglossus and the internal carotid artery before entering the base of the skull and that these be sent for final histological assessment. Then carefully stop the bleeding and complete the neck preparation around the anterior neck preparation, which is passed without any problems while sparing the outlets of the facial vein and superior thyroid. The wound is then carefully rinsed again and the bleeding is stopped once more. After insertion of a Redon drainage, two-layer wound closure. Further procedure depends on the histological results. If a marginal sample in the area of the vagus nerve, hypoglossal nerve or internal carotid artery proves positive, a further revision of the neck dissection should be discussed with the patient. However, this would mean a further radical procedure with removal of the hypoglossal and vagus nerve and, if necessary, closure of the internal carotid artery. If the primary is not found during the CUP panendo, the patient should then undergo radiochemotherapy as soon as possible.