Malignant tumor of the parotid gland
Introduction
Introduction to parotid malignant tumor Malignant tumor of parotidgland is mostly derived from salivary gland or glandular epithelial cells, which are common in mucoepidermoid carcinoma, malignant mixed tumor, adenoid cystic carcinoma and adenocarcinoma, accounting for 80% to 90%. basic knowledge The proportion of sickness: 0.002% - 0.005% Susceptible people: no special people Mode of infection: non-infectious Complications: facial paralysis
Cause
Causes of salivary gland malignancies
Causes
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Pathogenesis
1. Mucoepidermoid carcinoma:
It is a common malignant tumor of the parotid gland, which is derived from the ductal epithelium of the parotid gland. It is mainly composed of epidermoid cells, mucous cells and intermediate cells (basal cells). It is classified into highly malignant (lowly differentiated) and low malignant according to histological features. Highly differentiated type, two types, highly malignant epidermoid cells and intermediate cells, low malignant mainly differentiated mature mucus cells and intermediate cells, but these two types are still difficult to distinguish, intermediate cells It can differentiate into epidermal-like cells or mucous cells, and the tumor has no capsule, so it often infiltrates into surrounding tissues without clear boundaries.
2. Adenoid cystic carcinoma:
Also known as cylindrical tumor adenocarcinoma, cylindrical tumor, is a common type of malignant tumor of the salivary gland, but is not common in the parotid gland, derived from the epithelial cells of the parotid gland, the cancer cells are mainly glandular epithelial cells, like the epidermal basal cells, Polygons, often forming lumps or trabeculae of varying sizes, contain many adenoid vesicles in the mass, trabeculae are mostly solid, often surrounded by myoepithelial cells, and dense fibers between the lumps and trabeculae The mass is divided into lobulated, adenoid vesicles contain mucus, and the fibrous tissue between the tumor cells has a glassy change.
3. Malignant mixed tumor and mixed tumor malignant:
Most scholars believe that malignant mixed tumors are caused by malignant mixed tumors. The pathology shows that some of them are benign mixed tumors, and some of them are adenocarcinoma, squamous cell carcinoma, or undifferentiated carcinoma. Both benign can be seen. The part of the lesion that migrates to the malignant lesion, the malignant mixed tumor appears as basal cell-like cells or polymorphic cell-like cells. The cancer capsule is incomplete or non-enveloped, and the growth is slow, which can last for several years or even more than 10 years. If micronecrosis and hemorrhagic foci are found in mixed tumors, dystrophic calcification and matrix ossification, vitreous changes, and marginal invasive growth should all be considered signs of malignant transformation.
4. Adenocarcinoma:
Also known as nonspecific adenocarcinoma, a histologically varying degree of glandular differentiation, but not classified as a malignant tumor of a histopathological type, cancer cells may be from the reserve cells of the fistula, Often occurs in the parotid gland, is an irregular hard mass, generally no capsule, no obvious boundary with surrounding tissues, adenocarcinoma tissue complex, undifferentiated polygonal cells, or highly differentiated cylindrical cells, more obvious abnormalities, cancer The cells are arranged in a tubular or adenoid structure, and sometimes the ducts are expanded to form microcapsules, which contain viscous secretions, and the adenocarcinoma is a highly malignant tumor.
5. Acinar cell carcinoma:
It accounts for 7.2% to 19% of malignant tumors of the salivary gland. It occurs mostly in the shallow and tail parts of the parotid gland. It is locally destructive and is a low-grade malignant tumor. The texture of the tumor is hard, the surface is not smooth, and the leaf is lobulated. Although there is a capsule, Thin, but some incomplete, cancer cells infiltrated in the capsule, cancer cells composed of acinar-like cells, fistula-like cells, vacuolar cells, clear cells and non-specific gland cells constitute different types of tumor cells, cancer cells are larger Polygon, rich in cytoplasm, granular or vacuolated, nuclear round, small, central, and mitotic.
6. Squamous cell carcinoma:
Often occurring in the malignant transformation of mixed tumors, sometimes primary squamous cell carcinoma or poorly differentiated mucoepidermoid carcinoma, is inconclusive, mostly derived from ductal epithelial squamous cells, is a highly malignant tumor.
Prevention
Parotid malignant tumor prevention
1. Strengthen physical exercise, enhance physical fitness, and exercise more in the sun. Excessive sweating can excrete acidic substances in the body with sweat, avoiding the formation of acidic constitution. Have a good attitude to cope with stress, work and rest, do not fatigue.
2. Don't eat too much salty and spicy food, don't eat food that is overheated, too cold, expired and deteriorated; those who are frail or have certain genetic diseases should eat some anti-cancer foods and high alkali content as appropriate. Alkaline foods, maintain a good mental state to develop good habits, stop smoking and limit alcohol.
Complication
Parotid malignant tumor complications Complications
Malignant tumors of the salivary gland may be complicated by malignant mixed tumors, which appear as basal cell-like cells or polymorphic cell-like cells. The tumor capsule is incomplete or non-enveloped and grows slowly for several years to more than 10 years. If the tumor suddenly increases significantly, the texture becomes hard, and local pain, numbness or facial paralysis occurs within a few months, it should be suspected. The possibility of malignant transformation, the worse the later, easy to metastasize to the lungs, bones and brain.
Symptom
Parotid malignant tumor symptoms common symptoms nodular facial nerve spasm growth slow brain metastasis squamous cell carcinoma
1. Mucoepidermoid carcinoma:
Most mucoepidermoid carcinomas are low-grade, slow-growing, hard, smooth or nodular, active, and if the tumor is involved in the gland, the tissue is fixed, with pain, facial paralysis, 2/3 patients have regional Lymph node metastasis, 1/3 of patients have distant metastasis after 5 years, 15% of facial nerve spasm, if the diagnosis is correct, the treatment is standardized, the prognosis is good, the 5-year survival rate can be close to 90%, and 10% of patients show Highly malignant, the recurrence rate of low-grade malignant is 15%, and the recurrence rate of high-grade malignant is 60%.
2. Adenoid cystic carcinoma:
The cancer is round or oval, with a size of 2 to 4 cm. The boundary with the surrounding tissue is unclear. It grows slowly and has a long course of disease, but it is locally destructive. It is often characterized by nerve expansion, so there is pain in the early stage. And facial paralysis, even after a long time of pain, the tumor is found, 40% have blood transfer, and the lungs, liver, bone and regional lymph node metastasis often occur in the late stage. Because the boundary is difficult to determine, it is difficult to completely remove the surgery, so it is easy to relapse after operation. .
3. Malignant mixed tumor and mixed tumor malignant:
It is caused by malignant mixed tumors, which grow slowly. It can last for several years or even more than 10 years. If the mass suddenly increases significantly in a few months, the texture becomes hard, and local pain, numbness or facial paralysis is suspected. For the possibility of malignant transformation, the malignant mixed tumor has a poor prognosis, and it is easy to metastasize to the lungs, bones, and brain, and most of them die within 1 year of metastasis.
4. Adenocarcinoma:
Often occurs in the parotid gland, an irregular hard mass, no obvious boundary with surrounding tissues, easy to invade nerve tissue and blood transfer to the lungs and bones, the prognosis of this disease is poor, the recurrence rate is as high as 67.2%, so it should be given after surgery Radiation therapy to reduce recurrence, common cervical lymph node metastasis (46.6%), so surgery should be selective cervical lymphadenectomy, the 5-year survival rate of salivary gland cancer is 45%.
5. Acinar cell carcinoma:
The clinical manifestations are similar to those of mixed tumors. The growth is slow, the course is long, and it is asymptomatic. About 1/3 of them occur simultaneously or successively on both sides of the parotid gland. The tumor is hard and the surface is not smooth. The surgical resection is not complete, often leading to recurrence. Recurrence, and then radical cure is very difficult, patients die more than local spread of the tumor or distant metastasis, the 5-year survival rate is about 80%.
6. Squamous cell carcinoma:
Invasive growth, advanced surface skin can be ulcerated, secondary infection and hemorrhage, and involving the facial nerve and facial paralysis, about 15% of such tumors have regional lymph node metastasis and distant metastasis, the 5-year survival rate is 24%.
Examine
Examination of parotid malignant tumors
Histopathological examination is an important basis for a clear diagnosis. Common methods are:
1. Fine needle aspiration cytology:
It has the advantages of simplicity, rapidity, safety and less damage. The diagnostic coincidence rate is high. It can not only distinguish the benign and malignant tumors, but also determine the pathological type. The diagnostic accuracy of malignant tumors can reach 64.7%~97%, and postoperative The coincidence rate of histopathological control malignant tumors was 82.8% (Ma Daquan, 1988). Because the organization was very small, sometimes the diagnosis was difficult to determine.
2. Biopsy:
For parotid malignant tumors, in addition to the skin ulceration and advanced surgery, and must be clear histopathological diagnosis, it is generally inappropriate to use biopsy.
1. Parotid gland angiography:
Applicable to clinically undiagnosed patients, angiography can show the disorder of the catheter system caused by tumor compression, catheter distortion, displacement, interruption and irregular filling of acinar, contrast agent spillover formation of tumor erosion catheter, the size of the point Changes such as lamellae, this examination indirectly reflects the presence of lesions, but does not help to identify the nature of the tumor.
2. Type B ultrasound:
Can be used as a routine examination of the parotid mass, in addition to the actual size of the tumor can be measured, found in tumors less than 1cm in diameter, can also be based on the internal echo and its relationship with the perimeter to roughly distinguish its good, malignant, benign performance is clear, The internal echo is homogeneous, and the posterior wall has enhanced performance. The slightly larger mixed tumor can see the nodular nodular appearance, the malignant multi-contour boundary is unclear, the internal echo is highly inhomogenous solid dark area, and the posterior wall is reflected. The attenuation or disappearance of the sonogram, the diagnostic coincidence rate of up to 78.6% (Yu Guangyan, 1988), but the display of deep parotid tumors is not affected by the jaw bone.
3.CT and MRI:
Can determine the location, size, depth and depth of the tumor, and the relationship with the surrounding tissue, with or without infiltration, especially for the differentiation of deep parotid tumors and parapharyngeal space tumors and its relationship with the large vessels of the neck showed good, malignant performance The shape is irregular, the realm is blurred, and the density is uneven.
Diagnosis
Diagnosis and differentiation of malignant tumors of the salivary gland
diagnosis
1. History and clinical manifestations:
Patients with parotid gland tumors often find symptoms of the masses. In addition to careful understanding and analysis of the history of the disease, it should be often thought that the tumor is inflammation or tumor; if the tumor is determined to be benign or malignant; whether it is other than extraglandular tissue Lesion.
Some malignant tumors have no typical malignant manifestations, and sometimes have a long course of disease. At first, there is no pain, and it is easily misdiagnosed as benign.
2. Laboratory inspection and auxiliary inspection:
The results support malignant tumors of the parotid gland.
Differential diagnosis
1. Parotid lymph node and nodular SjÖgren syndrome.
2. Primary submandibular tumor:
The mass in the posterior fossa can be very similar to the deep parotid tumor of the parotid gland. Typical symptoms include ear symptoms of the eustachian tube, such as tinnitus, ear sensation and hearing impairment, persistent pain or paresthesia in the mandibular nerve distribution area, and the opening is biased toward the affected side or opening. Difficulties, the X-ray mandibular lateral radiographs often have deep sigmoid notch, and the condyle is compressed and deformed; the nasal epithelium shows that the maxillary sinus of the affected side becomes less compressed, and the sputum is mutated. CT or MRI will help diagnosis.
3. The cervical transverse process is too long:
The first cervical vertebra, also known as the atlas, its transverse process is located at the midpoint of the line from the tip of the mastoid to the mandibular angle. At the posterior margin of the mandibular branch, it can be reached when the development is too long. The myofas that attach to it often has inflammation and pain. Discomfort, palpation hard and fixed parallel tenderness, quite similar to deep parotid tumor of the parotid gland, palpation protuberance and tenderness are more limited. The diagnosis method can be used to puncture the target pain point with a 5 gauge needle or acupuncture. In the film, the needle tip is aligned with the transverse process, and a B-ultrasound is performed to exclude the space-occupying lesion in the parotid gland.
4. Eosinophilic lymphogranuloma:
The parotid gland is a predilection site. The clinical features are more than 95% male, young or middle-aged. There are single or multiple nodules in the parotid gland. There is a history of ablation with local or anterior skin itching, and peripheral blood eosinophils. Direct counting can be as high as 1000/mm3 or more, with diagnostic value, the disease is generally sensitive to radiation, and a small amount of radiation can be cured.
5. Metastatic tumors:
The scalp, eyebrows, eye and nasopharyngeal malignant tumors can all metastasize to the parotid lymph nodes. Although the incidence is not high, it is seen in clinical practice. Organs below the clavicle such as the lungs, liver cancer metastasis is occasionally seen and For the first time, it is necessary to perform a nasopharyngeal examination on the deep deep mass of the parotid gland.
