[A Case of Cervical Lymph Node Metastasis from an Unknown Primary Cancer Controlled with Immunotherapy, Chemotherapy, and Surgery].

We present a case of cervical lymph node metastasis from an unknown primary cancer that was controlled with immunotherapy, chemotherapy, and surgery. The patient, a 61-year-old man, was referred to our department for treatment of a lesion in the left cervical lateral area. At the initial visit, the mass was covered by reddened skin and was elastic, hard, and immobile on palpation. The presence of a malignant disease such as malignant lymphoma or lymphadenitis because of infection by tubercle bacillus or Epstein-Barr virus was suspected on the basis of the clinical and magnetic resonance imaging findings. Biopsy and resection of the cervical mass was performed under general anesthesia. Because the pathological diagnosis during surgery indicated squamous cell carcinoma, the surgical approach was changed to neck dissection. Head, neck, and thoracic computed tomography and other examinations were performed to locate the primary cancer, but its origin remained unknown. Postoperative therapy consisted of chemotherapy and immunotherapy. The patient has been followed up for 4 years and 10 months without any evidence of recurrence.