A 64-year-old man presented with symptoms derived from superior vena cava syndrome and airway stenosis caused by a huge right upper-lobe mass of the lung. Physical examination revealed a large ulcerated mass in the right palatine tonsil. Histological findings of the biopsied specimens obtained from the lung mass and the tonsillar tumor showed small cell carcinoma. Consequently, diagnosis of extensive-stage small cell lung cancer with isolated unitonsillar metastasis was made. The patient received combination chemotherapy with carboplatin and etoposide, resulting in a partial response. The metastatic tonsillar tumor completely resolved after chemotherapy alone and there was no recurrence until his death.