After induction of anesthesia, tracheoscopy is first performed with the 0° scope: this reveals inconspicuous mucosal conditions subglottically up to the carina. Now orotracheal intubation by the surgeon. First flexible esophagogastroscopy: Here the mucosal conditions are unremarkable on all sides. Now proceed to pharyngoscopy/laryngoscopy: Apart from the following findings, there are no further abnormalities in the entire oropharynx, hypopharynx and larynx region, in particular the tonsil lobe, base of tongue, vallecula, piriform sinus on both sides, esophageal entrance, postcricoid region and in the endolarynx. Now insertion of the mouth retractor and inspection of the oral cavity: An approx. 1.5 cm large, partially exulcerated mass is seen, which is located laterally on the underside of the tongue and extends to the lateral floor of the mouth. The mass is approx. 1 cm away from the left Wharton's duct. The entire mass is now incised with a safety margin of approx. 1 cm. Care is taken to maintain a sufficient distance in the area of the tongue muscles and in the caudal lateral area the resection extends to the Wharton's duct. The latter is injured and must then be marsupialized. Part of the sublingual gland is also resected posteriorly. The tumor specimen is now completely excised and sent for frozen section diagnostics with suture marking and diagnosed as R0. Careful hemostasis. Marsupialization of the Wharton's duct with 5.0 Monocryl sutures. Placement of a TachoSil swab on the muscle fiber to prevent secondary bleeding. Completion of the procedure without bleeding or complications. The patient should be presented at our tumor conference to decide whether to perform a neck dissection and/or adjuvant therapy.