두경부 원발부위 불명암에서 치료 후 발견된 비인두암

Nasopharyngeal cancer found after treatment of unknown primary cancer in the head and neck

Despite adequate diagnostic work-up, unknown primary carcinoma(UPC) of the head and neck cannot be detected in approximately 2- 3% of patients.(1,2) There are several explanations for a cervical metastasis in the absence of a primary tumor. Here in, we report 2 patients, who were diagnosed with nasopharyngeal cancer after treatment of unknown primary cancer of the neck. Both patients had radical neck dissections and chemoradiation therapy, but 1 patient showed nasopharyngeal cancers 4 years after treatment and the other patient at 9 months after treatment for the unknown primary cancer. Therefore, we report 2 cases of nasopharyngeal cancer, which were diagnosed after treatment of unknown head and neck primary site.