Mr. <PATIENT_NAME> is diagnosed with primary carcinoma of the tongue margin on the left. Preoperative MRI and PET-CT image diagnostics indicated a CUP syndrome with a large metastasis in the caudal parotid region. A gross needle puncture was performed in domo 4 weeks ago in LA. A metastasis at the lower parotid pole was biopsied and a squamous cell carcinoma was confirmed. Now, due to a small ulcer on the left edge of the tongue, a primary tumor in the oral cavity is suspected. Therefore indication for intraoperative panendoscopy and frozen section biopsy of the suspected ulcer as well as the procedure described above.