Few people think about where the salivary gland is located. While she regularly performs her functions and does not cause discomfort, they do not pay much attention to her. Salivary gland adenomas may differ in their histological and morphological structure. They, like other neoplasms, are malignant and benign. Benign tumors develop rather slowly and do not manifest themselves with discomfort or other symptoms. Malignant tumors grow rapidly, bleed into neighboring organs and tissues, cause pain and damage to the nerves of the face.
Definition
Where is the salivary gland located? First of all, it is worth noting that this is a paired alveolar-serous organ, located under the skin down and anterior to the auricle. Its main function is the secretion and accumulation of saliva. The liquid contains a large amount of sodium and potassium chlorides, as well as amylase. It creates an acidic environment in the oral cavity with a pH below 6. Both glands can secrete up to half a liter of saliva per day.
Adenomas of the salivary gland are benign, intermediate or malignant neoplasms that form from small or largesalivary glands. Among all tumor processes, salivary glands account for about a percent. This is a fairly high figure. Changes can start at any age, but are most common in middle and old age (40-60 years old) and are twice as common in women as in men.
Neoplasms are prone to malignancy, recurrence and metastasis, therefore they are of interest to dentists and maxillofacial surgeons.
Reasons
Why a salivary gland adenoma occurs is not completely known. Physicians have suggestions that the appearance of a tumor may be associated with a previous injury to this area or inflammatory diseases, as well as mumps (mumps). But not all patients have a history of such cases.
Some scientists insist that congenital tissue dystopia may be the cause of salivary gland tumors. In addition, oncogenic viruses such as Epstein-Barr, cytomegalovirus (especially types 16, 18, 31 and 32) and herpes simplex virus should not be discounted.
But these are not all cases when salivary gland adenoma can develop. The reasons must be sought in the person's lifestyle (chewing tobacco or using drugs), his living and working environment (excessive sun exposure, frequent radiation of the head and neck, radiation therapy for diseases of the thymus or thyroid gland). There is an opinion that the pathology is associated with an increase in cholesterol levels, a lack of vitamins in food and hormonal disorders.
It is believedthat at risk are workers in the woodworking, metallurgical and chemical industries (deposition of s alts of heavy metals), hairdressers.
TNM classification
For convenience in diagnosing and treating salivary gland adenoma, an international classification is used to make it easier to determine the stage of the process:
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T (tumor) - tumor size:
- T0 - adenoma could not be detected;
- T1 - diameter of the neoplasm less than 2 cm;
- T2 - diameter up to 4 cm, but does not go beyond the gland;
- T3 - size from 4 to 6 cm, the facial nerve is not affected; - T4 - diameter is more than 6 cm, spread to neighboring tissues, affects the cranial nerves.
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N (nodes) – regional lymph nodes:
- N0 – no metastases;
- N1 – one node affected, tumor up to 3 cm;
- N2 – affected several nodes, the size of the tumor is from 3 to 6 cm;- N3 - many nodes are affected, the diameter of the neoplasm is more than 6 cm.
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M (metastasis) - metastases:
- M0 - no distant metastases; - M1 - there are distant metastases.
Thanks to this system, it was possible to simplify the diagnosis and prognosis of the development of the disease. And the alphanumeric code allows you to use it in any country in the world.
Morphological classification
Adenoma of the parotid salivary gland can be of several types, differing from each other in histological and morphological structure:
- Epithelial tumor. Can develop from tissuesboth large and small salivary glands. It is characterized by the growth of the epithelium in the lumen of the ducts in the form of papillae, cribriform and tubular structures.
- Monomorphic adenoma. A benign formation consisting of glandular tissue. It develops imperceptibly, mainly in elderly men. It has a round or oval shape with an elastic consistency.
- Adenolymphoma repeats the morphology of a monomorphic adenoma, but inside the glands it also contains lymph.
- Sebaceous adenoma is a well-defined tumor formed from several nests of cystic sebaceous cells. May develop at any age. Painless, has a yellowish color. Once removed, it never metastasizes.
- Canalicular adenoma consists of prismatic epithelial cells that are collected in bundles. The average age of patients with this type of tumor is 65 years. In addition to the salivary gland, the adenoma also affects the upper lip and cheek.
- Basal cell adenoma. Benign, consisting of basal cells. As a rule, it is a small dense knot of white color. Does not recur and does not malignize.
- Pleomorphic adenoma of the salivary glands can grow to large sizes, lumpy and dense. Usually benign, but in advanced stages, malignant cells may appear. Inside it contains fluid and fibroblasts. Can be treated surgically, but due to its proximity to the facial nerve, surgeons may have difficulties.
Symptoms
Benign adenomaparotid salivary gland develops very slowly, sometimes for years. It does not cause any subjective sensations, but over time it can make the face asymmetrical. This is the reason for going to the doctor. After removal, such tumors can recur in 6 percent of cases. If the neoplasm is located close to the pharyngeal process of the parotid salivary gland, then this can cause swallowing problems, ear pain and lockjaw muscles.
How does an intermediate salivary gland adenoma manifest itself? Its symptoms are similar to both benign and malignant tumors. It is characterized by rapid infiltrative growth, destroys the tissues around it. May recur and give distant metastases to the lungs and bone tissue.
Malignant neoplasms occur both independently and after malignancy of a benign tumor. They grow rapidly, penetrating into the surrounding tissues. The skin over the tumor is red, hot, stretched. May be ulcerated. Characterized by pain, disruption of the chewing muscles, an increase in neighboring lymph nodes and the presence of metastases.
Diagnosis
Tumor of the salivary gland is quite easy to detect. To do this, you need to conduct an examination with a dentist and an oncologist, collect complaints and find out the history of the disease. Particular attention should be paid to the morphology of the tumor, its size, consistency and mobility.
From instrumental studies, X-ray of the bones of the skull, ultrasound of the salivary glands, sialography (look at the patency of the ducts of the gland) andsialoscintigraphy (to detect distant metastases). The most reliable method is considered to be a puncture of the gland followed by a smear examination, as well as a tissue biopsy for histological and pathomorphological study.
CT of the salivary glands, chest X-ray or individual bones may be needed to clarify the extent of the process.
Treatment of benign tumors
If a patient is diagnosed with a benign formation of the salivary glands, then he has a direct road to the surgeon. Techniques for "husking" such tumors have long been developed. A small incision is made over the capsule of the affected gland, the adenoma is mobilized and removed. The doctor at the same time tries not to damage the contents of the tumor. This intervention is called "excholeation".
The removed tissue must be given for macro- and microscopic examination to confirm the diagnosis. The facial nerve is never removed as it is rarely affected. If the tumor develops in the submandibular glands, then both the tumor and the gland are removed.
Treatment of malignant tumors
Malignant adenoma of the salivary gland requires complex combined treatment. How is the operation going? Even before the intervention, it is necessary to conduct a course of gamma therapy in order to reduce the size of the tumor, as well as to prevent the occurrence of regional and distant metastases. The operation itself is performed a month after radiation therapy.
Some authors recommend total removal of the parotidglands together with the branches of the facial nerve as a single block, along with the extirpation of regional lymph nodes. If during the examination it was revealed that the neoplasm had grown into the bone tissue of the lower jaw, then this area also needs to be resected. But before surgery, you need to think about how to mobilize the rest of the bone.
In advanced cases, only palliative radiation therapy is recommended, since the tumor cannot be removed due to too loose tissues.
Forecast
For benign tumors after surgical treatment, the prognosis for life and he alth is favorable. The probability of recurrence is low, only one and a half percent. Malignant tumors proceed extremely unfavorably. The patient can be cured only in twenty percent of cases, and even after that there is a danger that the neoplasm will reappear. Metastases to other organs occur in almost half of the cases.
