Salivary gland, also called salivary gland, mainly includes three pairs of large glands (i.e. parotid gland, submandibular gland and sublingual gland) and a large number of small salivary glands mainly distributed in oral mucosal tissue.
According to incomplete statistics in China, malignant tumors of salivary glands account for 0.7%~1.6% of the whole body malignant tumors and 2.3%~10.4% of the head and neck malignant tumors. According to the data of some countries such as Britain and America, the incidence of salivary gland tumor is generally 1~3 people/100,000, accounting for 6% of head and neck tumors. The cause of salivary gland tumor is unknown, but some factors have been noticed, such as radiation causing salivary gland tumor has been reported.
The clinical manifestations of salivary gland tumors are as follows
1. Parotid gland tumor.
The most benign parotid tumors are pleomorphic adenomas, which account for about 80% of parotid tumors; malignant ones are mucous epidermis-like carcinomas, which account for about 10% of parotid tumors and 1/2 of parotid malignant tumors.
Painless lumps: Most of the benign parotid tumors are unintentionally found as painless lumps centered on the earlobe. They grow slowly and have a long duration of disease.
Pain: Pain in the mass around the earlobe, especially persistent pain with progressive worsening, is one of the signs of malignant tumor.
Inability to close one side of the eye, crooked corner of the mouth, etc.: The growth of malignant tumor will invade the facial nerve and cause symptoms of facial nerve dysfunction or paralysis.
2. Submandibular gland tumor.
Among submandibular gland tumors, benign and malignant account for about half each, or slightly more malignant than benign. The benign tumors are mainly pleomorphic adenomas, while the malignant ones are commonly adenoid cystic carcinoma and mucinous epidermis-like carcinoma. Adenoid cystic carcinoma, which accounts for about half of the malignant tumors.
Submandibular mass: painless and slow-growing ones are mostly benign, while malignant ones are occasionally painful or grow faster.
Semi-lateral tongue numbness or tongue pain: this kind of tumor is mostly adenoid cystic carcinoma.
Restriction of opening: Tumor involving surrounding tissues such as occlusal muscle may cause restriction of opening.
Distorted angle of mouth or tongue extension: It occurs when the tumor involves the mandibular branch of facial nerve or sublingual nerve.
3.Tumor of sublingual gland.
Tumors of sublingual gland are rare, accounting for about 1% of salivary gland tumors. Among them, malignant tumors account for more than 90%, with adenoid cystic carcinoma being the most common. Sublingual tumors are not easily detected and can have the following manifestations.
Toothache
Numbness or tongue pain on one side of the tongue
Sublingual masses that prevent denture insertion
When the patient complains that there is no positive sign of tongue numbness or tongue pain on one side, the sublingual area should be palpated, and if there are hard nodules, malignant tumor should be highly suspected.
4.Small salivary gland tumor.
Small salivary glands are located in mucosal tissues and widely distributed, such as soft palate, hard palate, lips, cheeks, tongue, nasal cavity, larynx, nasopharynx and so on. Small salivary gland tumors account for 15% of salivary gland tumors, with benign and malignant accounting for about half of each. Clinical manifestations are
Masses in the above mentioned areas
toothache
Abnormal sensation or numbness in the palate, infraorbital area or upper lip
Gum swelling and tooth loosening
Swallowing discomfort and pain
Examination.
1. Clinical examination.
Palpation of parotid area and submandibular area, duplex sublingual area: generally benign tumors are softer to palpation and have clear circumference, while malignant tumors are more rigid and often have unclear circumference.
2. Imaging examination.
1) B-ultrasound: the mass lesion below 1cm can be displayed and the nature can be generally determined. But the qualitative diagnostic performance is not enough.
2) CT and MR: It can clearly show the location, size, extension of the tumor and its relationship with the surrounding anatomical structures.
3) Nuclear scan: It is specific for the diagnosis of parotid adenolymphoma.
3) Needle aspiration cytology: high diagnostic accuracy and high reference value for preoperative qualitative diagnosis.
Treatment.
1.Surgery
The treatment of salivary gland tumor is mainly surgical. For benign tumor, only tumor and gland can be removed, while for malignant tumor, the scope of resection should be determined according to the extent of tumor invasion, and if necessary, nerves, surrounding tissues (including bone) or skin should be removed. If there is lymph node metastasis, cervical lymph node dissection should be performed.
2.Radiotherapy
Radiation therapy is an important adjuvant treatment for salivary gland malignant tumor, but usually preoperative radiotherapy is not done. Indications for postoperative adjuvant radiotherapy.
Extensive tumor invasion, tumor invasion to the outer envelope
Low-grade malignant tumor, but the facial nerve is preserved by adhesion to it
Surgical residual or positive margins
Pathologically highly malignant tumor, such as undifferentiated carcinoma, squamous carcinoma, salivary gland ductal carcinoma, etc.
Recurrent malignant tumor
Prognosis.
Benign tumors of the salivary gland can be cured by simple excision. Malignant tumors are related to pathological type, primary site, surgical thoroughness and postoperative adjuvant therapy.