Few think about where the salivary gland is. While it regularly performs its functions and does not cause discomfort, it does not pay much attention. Adenomas of the salivary glands can differ in their histological and morphological structure. They, like other neoplasms, are malignant and benign. Benign tumors develop rather slowly and do not show discomfort or other symptoms. Malignant tumors grow quickly, they give cuttings to neighboring organs and tissues, cause pain and damage to the nerves of the face.
Where is the salivary gland? First of all, it should be noted 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. In the liquid, a large number of sodium and potassium chlorides, as well as amylases. It creates an acidic environment in the oral cavity with a pH below 6. During the day, both glands can secrete up to half a gallon of saliva.
Adenomas of the salivary gland are benign, intermediate or malignant neoplasms that are formed from small or large salivary glands. Among all the tumoral processes, the percentage of salivary glands is about one percent. This is a fairly high figure. Changes can begin at any age, but most often this happens in the middle and old age (40-60 years), and women are twice as likely as men.
Neoplasms are prone to malignancy, relapse and metastasis, and therefore are of interest to dentists and maxillofacial surgeons.
Why there is an adenoma of the salivary gland is not completely known. Doctors have speculation that the appearance of the tumor can be associated with the previous trauma of this area or inflammatory diseases, as well as with mumps epidemic (mumps). But not all patients in the history have such cases.
Some scientists insist that the cause of swelling of the salivary gland can be a congenital tissue dystopy. In addition, do not discount such oncogenic viruses as Epstein-Barr, cytomegalovirus (especially 16, 18, 31 and 32-type) and herpes simplex virus.
But this is not all cases when the adenoma of the salivary gland can develop. The reasons should be sought in the lifestyle of a person (chewing tobacco or using drugs), his habitat and work (excessive insolation, frequent irradiation of the head and neck, radiation therapy for thymus or thyroid disease). There is an opinion that the pathology is associated with an increase in cholesterol, lack of vitamins in food and hormonal disorders.
It is believed that workers at the wood processing, metallurgical and chemical industries (deposition of heavy metal salts), hairdressers are at risk.
Classification by TNM
For convenience in diagnosing and treating salivary gland adenoma, an international classification is used that facilitates the determination of the stage of the process:
- T (tumor) - tumor size:
- T0 - it was not possible to identify the adenoma;
- T1 - diameter of the tumor less than 2 cm;
- T2 - diameter up to 4 cm, but outside the gland does not go out;
- T3 - size from 4 to 6 cm, the facial nerve is not affected;
- T4 - diameter is more than 6 cm, it is distributed to neighboring tissues, it affects the cranial nerves.
- N (nodes) - regional lymph nodes:
- N0 - there is no metastasis;
- N1 - one node is affected, a tumor is up to 3 cm;
- N2 - several nodes are affected, tumor size - from 3 to 6 cm;
- N3 - many nodes are affected, the diameter of the tumor is more than 6 cm.
- M (metastasis) - metastases:
- M0 - there are no distant metastases;
- M1 - there are distant metastases.
Thanks to such a system, it was possible to simplify the diagnosis and predict the development of the disease. And the alphanumeric code allows you to use it in any country in the world.
The adenoma of the parotid salivary gland is of several species, differing in histological and morphological structure:
- Epithelial tumor. Can develop from the tissues of both large and small salivary glands. It is characterized by proliferation of epithelium in the lumen of the ducts in the form of papillae, crobras and tubular structures.
- Monomorphic adenoma. Benign formation, consisting of glandular tissue. It develops imperceptibly, mainly in elderly men. Has a round or oval shape of elastic consistency.
- Adenolymphoma repeats morphologically the monomorphic adenoma, but inside the glands it also contains lymph.
- The sebaceous adenoma is a clearly defined tumor, formed from several nests of cystically altered sebaceous cells. Can develop at any age. It is painless, has a yellowish color. After removal, never gives metastasis.
- The canal adenoma consists of prismatic epithelial cells that collect into 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. Do not recur and not malignant.
- Pleomorphic adenoma of the salivary glands can grow to large sizes, tuberous and dense. Usually benign, but at later stages can appear malignant cells. Inside it contains liquid and fibroblasts. It is susceptible to surgical treatment, but because of the proximity to the facial nerve, surgeons may have difficulties.
Benign adenoma of the parotid salivary gland develops very slowly, sometimes for years. It does not cause any subjective sensations, but over time can make a person asymmetric. This is the reason for going to the doctor. After removal, such tumors can recur in 6 percent of cases. If the neoplasm is closely located to the pharyngeal process of the parotid salivary gland, then this can cause a violation of swallowing, ear pain and trisus of the masticatory muscles.
How does the intermediate adenoma of the salivary gland manifest? Symptoms of it are similar to both benign and malignant tumors. It is characterized by rapid infiltrative growth, destroying the tissues around itself. It can recur and give distant metastases to the lungs and bone tissue.
Malignant neoplasms arise both independently and after malignization of a benign tumor. Grow quickly, penetrating into surrounding tissues. The skin above the tumor is red, hot, taut. Can be ulcerated. Typical pain, malfunction of the masticatory muscles, an increase in neighboring lymph nodes and the presence of metastases.
The tumor of the salivary gland is quite easy to detect. To do this, you need to check with a dentist and 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, radiography of the bones of the skull, ultrasound of the salivary glands, sialography (look through the ducts of the gland) and sialoscintigraphy (for the detection of distant metastases). The most reliable method is a puncture of the gland with subsequent examination of the smear, as well as biopsy of tissues for histological and pathomorphological examination.
To clarify the prevalence of the process may need CT salivary glands, chest X-ray or individual bones.
Treatment of benign tumors
If the patient is diagnosed with a benign salivary gland formation, then it is a direct way to the surgeon. For a long time, the techniques of "harvesting" such tumors have been developed. A small incision is made above 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. Such an intervention is called "ex-cholation".
Removed tissue is necessarily given to a macro and microscopic examination to confirm the diagnosis. The facial nerve is never removed, since it is rarely affected. If the tumor develops in the submaxillary glands, then both the neoplasm and the gland are removed.
Treatment of malignant tumors
Complicated combined treatment requires malignant adenoma of the salivary gland. How is the operation? Even before the intervention, it is necessary to conduct a course of gamma therapy to reduce the size of the tumor, as well as to prevent the emergence of regional and distant metastases. Immediately, the operation is performed one month after the radiation therapy.
Some authors recommend the complete removal of the parotid glands together with the branches of the facial nerve with a single block, together with the extirpation of the regional lymph nodes. If at the examination it was revealed that the tumor had grown into the bone tissue of the lower jaw, then this area also needs to be resected. But before the operation, 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 can not be removed due to too loose tissues.
For benign tumors after the spent surgical treatment, the prognosis for life and health is favorable. The probability of recurrence is low, only one and a half percent. Malignant tumors are extremely unfavorable. Cure the patient can only be in twenty percent of cases, and even after that there is a danger that the tumor will reappear. Metastases to other organs are found in almost half the cases.