[17] In our study, APC mutations were observed in 2.5% of cases, which is slightly lower than previous report. [18] STK11 mutations, found in 2.1% were observed in P281L within the kinase domain and all 5 patients with this mutation were stage IV with extensive lymph node metastases. The gene discussed is STK11; the disease is metastatic malignant neoplasm in the lymph nodes.