“…Adjuvant chemotherapy and radiotherapy have been administered in a few cases, but a definitive role of adjuvant treatment has not yet been established [ 2 - 4 , 8 , 9 ]. These tumors usually metastasize to regional lymph nodes before they spread to the lung, liver, brain, spinal cord, and bone [ 2 , 8 , 9 , 13 ]. In a meta-analysis of 72 cases, lymph node metastasis and distant metastasis were associated with significantly reduced survival.…”