Adenoid cystic carcinoma is one of the most common malignancies of the salivary glands and can occur at any age, with most cases occurring in middle age and older. There are more adenoid cystic disease in small salivary glands than in large salivary glands. Clinical manifestations: 1. The tumor is easy to spread along the nerve and often has neurological symptoms, such as pain, facial palsy, tongue numbness or sublingual nerve palsy. Tumor of palate can spread to skull base along palatal nerve. 2.Tumor infiltration is extremely strong, without boundary with surrounding tissues, sometimes even jumping. 3. Cancer is highly invasive and easily invades blood vessels to develop distant metastasis. About 40% of patients will have lung metastasis, followed by liver and bone metastasis. The time of metastasis can be early or late, and the latest one can be 3-5 years or even longer after the treatment of primary foci. For those who develop pulmonary metastases, there are usually no obvious conscious symptoms unless they invade the pleura and develop pleural fluid. Therefore, regular chest radiography should be routinely performed to determine the presence or absence of lung metastases. 4. The rate of cervical lymph node metastasis is very low. Treatment measures: The treatment of adenoid cystic carcinoma is mainly based on surgery, and after surgery, radiation therapy and chemotherapy must be added as comprehensive treatment. 1.Surgical treatment: Adenoid cystic carcinoma is highly infiltrative, so local enlargement resection is the main principle to cure adenoid cystic carcinoma, and the tissues around the tumor should be removed as much as possible, even some organs that seem normal to the naked eye, including jaw bone. Frozen section should be examined during surgery to determine the safety limit. 2.Radiotherapy: Adenoid cystic carcinoma has certain sensitivity to radiation, but it is difficult to be cured by radiotherapy alone. Postoperative adjuvant radiotherapy can significantly improve the survival rate of patients and reduce recurrence. Patients must receive radiotherapy after surgery. 3.Chemotherapy: Adenoid cystic carcinoma has a high rate of distant metastasis and high rate of hematogenous metastasis, especially metastasis to the lung, so it is appropriate to add prophylactic chemotherapy routinely after surgery. The National Salivary Gland Tumor Collaborative Group recommends PVF regimen (cisplatin, vincristine and 5-Fu). Prognostic evaluation: Adenoid cystic carcinoma is a very aggressive tumor, which gradually and widely spreads around the tumor through submucosa and fibrous tissue, and it also gradually expands along the nerves, therefore, the local recurrence rate is high; however, the tumor grows slowly and has a long survival time with tumor, therefore, most patients can obtain long-term survival.