Adenoid cystic carcinoma is a malignant tumor of exocrine glands. There are two types of tumor cells: glandular duct lining epithelial cells and myoepithelial cells, and the composition ratio of the two types of cells at different stages of differentiation is different, forming a combination of tubular type, adenoid type (sieve type) and solid necrotic type. Adenoid cystic carcinoma can occur in all exocrine glands, such as lacrimal gland, Bartholin’s gland, breast, etc. Adenoid cystic carcinoma can occur in all sites where there are glands, such as maxillary sinus, nasal cavity, thoracic cavity, abdominal cavity and pelvis. Adenoid cystic carcinoma is one of the common malignant tumors of salivary gland, and its incidence is second only to mucous epidermoid carcinoma. It occurs in the minor salivary glands of the palate, followed by the parotid, submandibular and sublingual glands. Adenoid cystic carcinoma is neurophilic in nature and has a strong local infiltration. The scope of tumor is very different between visual and imaging examination and microscopic examination. If the motor nerve is invaded, the corresponding nerve dysfunction will occur, such as facial nerve palsy, hypoglossal nerve palsy leading to hemianopia, etc. The clinical manifestations are varied and may include masses, scars, and inflammation. It can also manifest as toothache without pack fast. If there is no obvious reason for the appearance of conscious symptoms, adenoid cystic carcinoma should be highly alerted. Adenoid cystic carcinoma is prone to distant metastasis by blood, the most common being lung metastasis, followed by liver, bone and brain metastasis. Lymph node metastasis is relatively rare. The early diagnosis of adenoid cystic carcinoma is difficult because of the diverse clinical manifestations and slow growth. Adenoid cystic carcinoma in salivary glands, especially parotid and submandibular glands, often appears as a painless mass in the early stage, which is difficult to distinguish from pleomorphic adenoma. It is an indistinctly defined hard mass at the junction of the cheek, lip and floor of the mouth and hard and soft palate. The disease can occur at any age, but is concentrated in the 40-60 age group. There are no significant gender differences. Adenoid cystic carcinoma is often considered if neurologic symptoms are present and other associated signs are not compatible, such as abnormal sensation of facial skin, pain, facial palsy or facial muscle twitching, pain at the floor of the mouth, and limited tongue movement resulting in slurred speech. Unlike squamous cell carcinoma, adenoid cystic carcinoma of adenoid origin does not usually ulcerate when the mucosa is intact, but only when the tumor protrudes toward the oral surface and is traumatized. Most of the adenoid cystic carcinomas of macrosalivary gland origin are soft tissue masses. Ultrasound, CT and MRI have no characteristic changes, but they are helpful to determine the scope, especially the thickening of the associated nerve involvement, CT can show the enlarged round foramen, foramen ovale, stem mammary foramen and sublingual nerve canal, MRI can directly see the thicker nerve than the opposite side in addition to this performance. Chest radiograph and CT examination of lung metastases, PET-CT to determine the presence of systemic metastases, and bone scan to diagnose bone metastases. Differential diagnosis】 In the parotid and submandibular glands, it needs to be differentiated from pleomorphic adenoma, carcinoma in pleomorphic adenoma, basal cell adenocarcinoma and salivary ductal carcinoma. The World Health Organization officially classified ductal carcinoma of the salivary gland as one of the malignant tumors of the salivary gland in 1990. Because of its extremely high malignancy and poor prognosis, it has received increasing attention from oral and maxillofacial surgery colleagues. Ductal carcinoma is mostly seen in the elderly, mostly in the parotid gland. Pathologically, the cancer cells are arranged in nest-like, papillary or sieve-like shape, almost all of them have necrosis, and the tumor cells are medium in size, well-defined, with eosinophilic cytoplasm, deep-stained nuclei, multiple nucleoli and obvious nuclear division. The nucleus is darkly stained with multiple nucleoli, and the nucleus is clearly divided. The mucus is negative for Carmine staining and may contain PAS positive granules. Pimple-like necrosis in the center of the nest is the characteristic change of ductal carcinoma. Treatment is advisable to adopt surgical excision, selective neck clearance, and supplemented with postoperative radiotherapy and chemotherapy. Basal cell adenocarcinoma and epithelial-myoepithelial carcinoma have microscopic similarities with the disease, but immunohistochemistry can differentiate them, and basal cell adenocarcinoma has a better prognosis. Non-specific infections in the floor of the mouth and buccal and lip areas. Adenoid cystic carcinoma in these areas resembles cool inflammatory manifestations or scar-like changes without obvious symptoms of infection such as redness, swelling, heat and pain, or only sensory abnormalities such as tingling or numbness, requiring frozen pathological examination to confirm the diagnosis. Since the extent of lesions observed by the naked eye and the results obtained from pathological examination vary greatly, it is difficult to determine the extent of resection by the naked eye during surgery, so it is necessary to routinely send the cut edge for frozen pathological examination during surgery. Although the disease is slow-growing and can survive with the tumor for many years, it is very difficult to cure. In general, the tubular type has a better prognosis and the solid necrotic type is the worst. Local postoperative radiotherapy should be supplemented with high-dose radiotherapy to achieve certain efficacy, but the oral and maxillofacial areas generally have difficulty with doses above 70 GY. Although the response of fast neutron radiotherapy is larger, the effect on salivary gland malignant tumor is better than ordinary external irradiation. In the past decade or so, inter-tissue implantation of 125I radioactive particles has been used for the treatment of adenoid cystic carcinoma with obvious effect, and it should be the first choice for those who have the condition. Adenoid cystic carcinoma occurring in sublingual gland, floor of mouth and submandibular gland has poor prognosis. For the treatment of distant metastases, chemotherapy and biological therapy are mostly used, but the effect is poor. In the range of metastases from 0.5 to 3 cm, gamma knife treatment is recommended, and for those larger than 3 cm, 125I radioactive particle intervention is used. Clinical adenoid cystic carcinoma has the following characteristics: 1. the extent of naked eye lesion does not match the actual lesion extent at all, especially in the palate. Clinically, a 1 cm lesion at the junction of soft and hard palate still has suspicious cancer tissue at the skull base after extensive resection or even bilateral maxillary resection; 2. the extent of lesion does not match the systemic condition at all. although the patient has extensive metastasis in both lungs, he may not feel any discomfort and does not affect The course of the disease is completely inconsistent with the degree of malignancy. Most of adenoid cystic carcinoma can survive for more than 5 years without treatment, but the extent of local invasion, the number of metastases, and the high degree of difficulty in cutting clean are very obvious. Some people have already metastasized in both lungs at the time of initial diagnosis, but they can still survive for many years, and some of them can still live on their own for more than 23 years. Adenoid cystic carcinoma is characterized by neurophilic properties and early occurrence of distant metastasis, which is generally difficult to be excised and is extremely aggressive despite its slow growth. Clinically, the best means of early lung metastasis detection is CT plain scan, and those with normal preoperative chest radiographs should be supplemented with lung CT once the disease is identified, according to which, we have identified a considerable number of patients with early lung metastasis. 125I radiation particle application has better efficacy. Conventional radiotherapy requires a higher dose to be effective, and is generally ineffective at less than 50GY. Fast neutron radiotherapy is six times more effective than normal radiotherapy, but far less effective than 125I radiation particles. Adenoid cystic carcinoma is not sensitive to chemotherapy. Postoperative patients are usually reviewed once every six months, mainly to check local and lung areas. If there is lung metastasis, liver and bone tissue, mainly ribs and vertebrae, also need to be checked. In general, bone and liver metastases without lung metastases are extremely rare. Adenoid cystic carcinoma of the parotid area is prone to facial nerve paralysis, and according to the traditional method, the parotid gland should be removed and the facial nerve should be sacrificed, while adenoid cystic carcinoma of the floor of the mouth is prone to invade the external tongue muscle and tongue muscle, and invade the lingual nerve and the hypoglossal nerve, and according to the traditional method, most of the tongue tissue and part of the mandibular bone should be removed, and even if it is widely removed, it is difficult to cut it. We only take 125I radiation particle treatment for these patients. After 1-2 months of treatment, the swelling became soft and disappeared, and facial palsy and sublingual nerve palsy recovered. Therefore, after the diagnosis of the disease is confirmed by intraoperative cryopathology, we do not continue to enlarge the resection and recommend supplementary radioactive particle implantation. Since the half-life of radioactive particles is 59 days, they have no effect at all after 200 days. If the tumor disappears completely after 2-3 months of treatment, it can be observed, or the radioactive particles can be implanted again after 6 months. According to the clinical application, through more than 5 years of observation, the vast majority of them can be implanted once, and suspected recurrence or clinically determined to have recurred before additional implantation, and very few patients are currently implanted 4 times in total. However, due to the slow growth of the disease itself, it remains to be observed whether a complete cure can be achieved. One thing is certain, the method is very effective in controlling the growth of adenoid cystic carcinoma, which is unlike any other method so far. Due to its neurophilic characteristics, extra attention is paid to the foramen ovale, foramen ovale, foramen caudatum and the external opening of the sublingual nerve canal depending on the site when implanting radioactive particles. When the lesion invades the orbital apex, the base of the middle cranial fossa and around the internal carotid artery, it is recommended to intervene with subnavigation radioactive particles. Avoid injury to the optic nerve, cavernous sinus and internal carotid artery.