Cervical lymph node metastases with occult primary site.
D000367:Age Factors; D002294:Carcinoma, Squamous Cell; D006258:Head and Neck Neoplasms; D006801:Humans; D008197:Lymph Node Excision; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D009303:Nasopharyngeal Neoplasms; D012737:Sex Factors