Few people wonder where the salivary gland is. While she regularly performs her functions and does not cause discomfort, they do not pay much attention to her. Adenomas of the salivary glands 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 discomfort or other symptoms. Malignant tumors grow quickly, give screenings to neighboring organs and tissues, cause pain and damage to nerves of the face.
Definition
Where is 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. During the day, both glands can secrete up to half a liter of saliva.
Salivary gland adenomas are benign, intermediate, or malignant neoplasms that form from the small or large salivary glands. Among all the tumor processes, the salivary glands account for about a percent. This is a fairly high rate. Changes can begin at any age, but most often it happens in middle and old age (40-60 years), and women are twice as likely as men.
Neoplasms are prone to malignancy, relapse and metastasis, therefore, they are of interest to dentists and maxillofacial surgeons.
Causes
Why salivary gland adenoma occurs is not fully known. Doctors have speculated that the appearance of a tumor may be associated with a previous injury to this area or inflammatory diseases, as well as with mumps (mumps). But not all patients have a history of such cases.
Some scientists insist that congenital tissue dystopia may be the cause of a salivary gland tumor. In addition, oncogenic viruses such as Epstein-Barr, cytomegalovirus (especially the 16th, 18th, 31st and 32nd type) and herpes simplex virus should not be discounted.
But these are not all cases where salivary gland adenoma may develop. The reasons must be sought in a person’s lifestyle (chewing tobacco or drug use), his environment and work (excessive insolation, frequent exposure to the head and neck, radiation therapy for diseases of the thymus or thyroid gland). It is believed that pathology is associated with an increase in cholesterol, a lack of vitamins in food and hormonal disorders.
It is believed that at risk are workers in the woodworking, metallurgical and chemical industries (deposition of salts of heavy metals), hairdressers.
TNM classification
For convenience, the international classification is used to diagnose and treat salivary gland adenoma, which facilitates the determination of the stage of the process:
- T (tumor) - tumor size:
- T0 - failed to identify the adenoma;
- T1 - neoplasm diameter 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 greater than 6 cm, spread to neighboring tissues, affects the cranial nerves. - N (nodes) - regional lymph nodes:
- N0 - no metastases;
- N1 - one node is affected, the tumor is up to 3 cm;
- N2 - several nodes are affected, 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. - M (metastasis) - metastases:
- M0 - there are no distant metastases;
- M1 - there are distant metastases.
Thanks to this system, it was possible to simplify the diagnosis and prediction 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 is of several types, which differ in histological and morphological structure:
- Epithelial tumor. It can develop from the tissues of both 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, cribrotic and tubular structures.
- Monomorphic adenoma. A benign mass consisting of glandular tissue. It develops imperceptibly, mainly in elderly men. Has a round or oval shape of elastic consistency.
- According to morphology, an adenolymphoma repeats monomorphic adenoma, but inside the glands it also contains lymph.
- Sebaceous adenoma is a clearly defined tumor formed from several nests of cystically altered sebaceous cells. It can develop at any age. It is painless, has a yellowish color. After removal, it never gives metastasis.
- Canalicular adenoma consists of prismatic epithelial cells that collect in bundles. The average age of patients with this type of tumor is 65 years. In addition to the salivary gland, adenoma also affects the upper lip and cheek.
- Basal cell adenoma. Benign, consisting of basal cells. As a rule, this is a small dense knot of white color. It does not recur or malignant.
- Pleomorphic adenoma of the salivary glands can grow to large sizes, tuberous and dense. Usually benign, but in the later stages, malignant cells may appear. Inside itself contains fluid and fibroblasts. Amenable to surgical treatment, but due to the proximity to the facial nerve, surgeons may have difficulties.
Symptoms
Benign adenoma of the parotid salivary gland develops very slowly, sometimes for years. It does not cause any subjective sensations, but over time it can make a face 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 close to the pharyngeal process of the parotid salivary gland, this can cause a violation of swallowing, earaches and trismus of the masticatory muscles.
How does intermediate salivary gland adenoma manifest? Her symptoms are similar to both benign and malignant tumors. It is characterized by rapid infiltrative growth, destroys the tissues around it. It can 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 the surrounding tissue. The skin over the tumor is red, hot, taut. May be ulcerated. Pain, malfunctioning of the masticatory muscles, an increase in neighboring lymph nodes and the presence of metastases are characteristic.
Diagnostics
A salivary gland tumor is fairly easy to detect. To do this, you need to conduct an examination 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, X-ray of the bones of the skull, ultrasound of the salivary glands, sialography (see the patency of the ducts of the gland) and sialoscintigraphy (to detect distant metastases) are performed. The most reliable method is the puncture of the gland with the subsequent examination of the smear, as well as a tissue biopsy for histological and pathomorphological studies.
To clarify the prevalence of the process, salivary gland CT, chest x-ray, or individual bones may be needed.
Benign tumor treatment
If the patient is diagnosed with a benign formation of salivary glands, then he has a direct path 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. Such an intervention is called "exholation."
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 neoplasm and the gland are removed.
Cancer treatment
Complex combined treatment requires a malignant salivary gland adenoma. How is the operation? Even before the start of 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 appearance of regional and distant metastases. The operation is carried out directly a month after radiation therapy.
Some authors recommend complete removal of the parotid glands together with the branches of the facial nerve in a single block, together with the extirpation of regional lymph nodes. If during the examination it was revealed that the neoplasm sprouted 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 cannot be removed due to too loose tissue.
Forecast
For benign tumors after 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. The patient can be cured only in twenty percent of cases, and even after this there remains the danger that the neoplasm will reappear. Metastases to other organs are found in almost half the cases.