First, a panendoscopy is performed. This reveals a tumor of the left anterior palatal arch, the tonsil, which then extends over the vallecula to the hypopharynx. However, the piriform sinus of the left side is completely omitted by the tumor. The same applies to the entire right side of the hypopharynx and oropharynx. The tumor certainly does not reach the midline of the soft palate. From the tonsil, the tumor passes slightly onto the glossotonsillar groove. First adjust and expose the tumor with the FK retractor. Then start resection at the anterior palatal arch. From here, dissection down to the tonsil, which is then resected with tissue surrounding the tonsil capsule in the sense of a tumor tonsillectomy. The pharyngeal musculature is exposed. There is no evidence of deep tumor growth. The tumor is then developed further caudally. Here resection of the glossotonsillar groove with transition of the resection to the base of the tongue. A part of the base of the tongue is also resected here. Further dissection then caudally, towards the hypopharynx, where the tumor can then be safely removed at the entrance to the piriform sinus. Now take samples from the margins at the entrance to the piriform sinus, the anterior and posterior margins and the base of the tongue. It then becomes apparent that the tumor reaches the lingual epiglottis via the vallecula, so that a corresponding part of the lingual epiglottis is resected here as well. Now also take a marginal sample at the resection margin of the epiglottis. The area of the entrance of the piriform sinus at the front and at the epiglottis is then assessed by the pathologist as a carcinoma in situ in the frozen section, so that another resection is performed here. A resection is then performed on the epiglottis and the anterior piriform sinus entrance. If the mucosal aspect is absolutely inconspicuous macroscopically, the corresponding marginal samples are taken again from the epiglottis and the anterior piriform sinus entrance. When the marginal sample is taken, there is a somewhat heavier bleeding here from the depths, which can only be controlled with difficulty using monopolar coagulation. The area of the resection site can now hardly be exposed with the FK retractor, so that it is then decided not to carry out any further resection in depth, regardless of the result of the histological findings of the frozen section examination. If the wound is dry, all instruments are then removed. Then reposition the patient by tracheotomy. Perform a pretracheal transverse incision and then dissect in layers in depth. Exposure of the thyroid isthmus. Then separate the infrahyoid and infralaryngeal muscles at the midline. Clamping of the thyroid isthmus and separation of the thyroid muscle as well as bilateral repositioning. Then expose the anterior surface of the trachea, open the trachea between the 2nd and 3rd cartilage clasp, prepare a Björk flap and then suture the tracheostoma in a circular fashion, followed by reintubation onto an 8-gauge cannula. The intraoperative frozen section at the epiglottis is then assessed as tumor-free. The frozen section in the area of the resection site on the piriform sinus on the anterior wall is again described as carcinoma in situ. However, since a left neck dissection is required anyway in this patient with a positive lymph node status on the left side of the neck, another transoral laser resection should be performed in the area of the piriform sinus anterior wall on the left side in connection with this procedure. The procedure is therefore completed at this point. After extubation, the patient returns to the normal ward of the ENT clinic.