A 58 years old male patient presented with a left cervical metastasis of a poorly differentiated squamous cell carcinoma, which was diagnosed by fine needle aspiration cytology. Clinical examination, MRT scans and panendoscopy did not detect the primary tumour site. The positron emission tomography localized an uptake of FDG in the left sided base of the tongue. The patient underwent an ipsilateral modified radical neck dissection and a lateral pharyngotomy. In the left tongue base an induration was palpable which was resected with security distance. The histopathological examination showed a poorly differentiated squamous cell carcinoma with a largest extension of 5 mm x 10 mm.