Course of lectures (almost all) / Lecture 21 Salivary glands

Who is the study for?

The main indication for ultrasound examination of the salivary glands is the presence of any complaints in the patient. Most often, patients come to the doctor with the following problems:

• sharp pain in the submandibular or parotid area;
• local or general hyperthermia (increased temperature directly in the area of ​​the lesion or in the entire body as a whole);
• increase in the size of the salivary glands;
• dry mouth (xerostomia);
• the presence of compactions (tumors, stones) near the salivary glands.

If the above symptoms are present, as well as after a visual examination, palpation examination and history taking, the doctor, in addition to laboratory tests, refers the patient to an ultrasound scan. The method is used if it is necessary to carry out differential diagnosis for such pathologies as:

• inflammatory diseases of the salivary glands (acute and chronic sialoadenitis, viral and bacterial);
• adenoma;
• salivary stone disease;
• tonsil damage;
• tumor neoplasms (malignant and benign);
• individual anatomical anomalies;
• enlargement of nearby lymph nodes;
• dystrophic lesions of organ tissue.

During the study, specialists can assess the condition of the group of large salivary glands: parotid, sublingual, submandibular.

Theory and practical experience in ultrasound diagnosis of salivary gland pathology

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In domestic and foreign literature there are many works devoted to sialogy (from the Greek Sialon - saliva and logos - study) - the science of diseases and injuries of the salivary glands, methods of their diagnosis and treatment. According to various authors, diseases of the salivary glands account for up to 24% of all dental pathologies. Currently, in clinical practice, the most common are dystrophic, inflammatory diseases of the salivary glands (sialoadenoses, sialadenitis), as well as tumors and congenital malformations of the salivary glands. In addition, pathological changes in the salivary glands often accompany other diseases (diabetes mellitus, bronchiectasis, sarcoidosis, liver cirrhosis, hypertriglyceridemia, lymphogranulomatosis, etc.).

Various instrumental methods are used to diagnose diseases of the salivary glands [1]:

• radiography (if the formation of stones in the ducts of the salivary glands is suspected, but in 20% of the stones of the submandibular salivary glands and 80% of the parotid salivary glands are non-radiographically opaque);
• sialography (examination of the ducts of the salivary glands with a radiopaque substance, is rarely useful in differentiating tumors from inflammatory processes, but it can help differentiate the mass formation of the salivary glands from formations in neighboring tissues. In patients with suspected autoimmune disease of the salivary glands, a characteristic pattern of saccular expansion may be detected ductal system. In case of acute infection of the salivary glands, sialography should not be performed [2]);
• computed tomography together with sialography;
• ultrasound method (is the most accessible, safe and informative in the process of differential diagnosis of the pathological condition of the salivary glands).

Anatomy of the salivary glands [3]

There are three pairs of major salivary glands (SG) and many small ones. The large ones include paired parotid, submandibular and sublingual SGs. The parotid salivary gland (PSG) is located on the outer surface of the branch of the lower jaw at the anterior edge of the sternocleidomastoid muscle, as well as in the retromandibular fossa. Dimensions vary widely: length 48-86 mm, width 42-74 mm, thickness 22-45 mm. The OSJ is covered by the parotid fascia, which is its capsule and is tightly fused with it. Sometimes, at the anterior edge of the parotid duct, there is an additional lobule measuring 10-20 mm, which has its own duct flowing into the parotid. The parotid duct emerges from the gland at the border of its upper and middle thirds, then it passes along the outer surface of the masticatory muscle parallel to the zygomatic arch and turns 90° inward, penetrating the fatty tissue and buccal muscle. The projection of the parotid duct onto the skin of the cheek is determined on the line connecting the tragus of the auricle and the corner of the mouth. The parotid duct opens in the vestibule of the oral cavity at the level of 1-2 large molars. The diameter of the duct is on average 1.5-3.0 mm, its length is 15-40 mm. The thickness of the gland contains the branches of the external carotid artery, the facial nerve and its branches, and the auriculotemporal nerve. There are many lymph nodes around the OUSG and in its parenchyma (Fig. 1), which can serve as a primary or secondary collector for draining lymph from teeth and oral tissues.

Rice. 1.

Lymph nodes in the thickness of the parotid salivary gland.

The submandibular salivary gland (MSG) is located in the submandibular triangle between the body of the mandible and the anterior and posterior bellies of the digastric muscle. The dimensions of the gland are: anteroposterior 20-40 mm, lateral 8-23 mm, superior-inferior 13-37 mm. Posteriorly, the PNJ is separated from the OSJ by a process of the fascia propria of the neck. The medial surface of the gland in the anterior section lies on the mylohyoid muscle. The submandibular duct, bending over the posterior edge of this muscle, is located on the lateral surface of the hyoglossus muscle. Then it goes between the medial surface of the hyoid gland and the genioglossus muscle to the point of its exit in the area of ​​the hyoid papilla. The facial artery and its branches, the lingual artery and the veins of the same name pass through the gland.

The sublingual salivary gland (SSG) is located on the floor of the mouth in the sublingual region parallel to the body of the lower jaw. The dimensions of the gland are: longitudinal 15-30 mm, transverse 4-10 mm and vertical 8-12 mm. The duct of the parathyroid gland passes along its inner surface and opens in the region of the anterior section of the sublingual ridge independently or together with the submandibular duct. Sometimes the PJS duct flows into the middle section of the PJS duct.

The minor salivary glands - labial, buccal, lingual, palatine, incisive - are located in the corresponding areas of the mucous membrane. They can be a source of development of adenocarcinomas of the oral cavity.

Pathology of the salivary glands

SG malformations are rare. The most common are anomalies in the size of the glands (agenesis and aplasia, congenital hyperplasia (Fig. 2) and hypoplasia), their location (heterotopia, accessory glands), and anomalies of the excretory ducts (atresia, stenosis, ectasia, cystic transformation, ductal dystopia).

Rice. 2.

Hyperplasia of the left sublingual salivary gland.

Sialadenitis is a large group of polyetiological inflammatory diseases of the gastrointestinal tract (Fig. 3). Primary sialadenitis - sialadenitis considered as an independent disease (for example, mumps). Secondary sialadenitis is sialadenitis that is a complication or manifestation of other diseases (for example, sialadenitis with influenza). The echographic picture for different etiologies is not very specific. Etiology has clinical significance in determining treatment tactics.

Rice. 3.

Sialadenitis of the right submandibular salivary gland.

According to the etiological factor, sialadenitis is classified [4] into:

1. sialadenitis developing under the influence of physical factors (traumatic sialadenitis, radiation sialadenitis (Fig. 4) occurs during radiation therapy of malignant tumors of the head and neck);
2. sialadenitis developing under the influence of chemical factors (toxic sialadenitis);
3. infectious sialadenitis (routes of infection penetration into the fluid: stomatogenic (through ducts), contact, hematogenous and lymphogenous);
4. allergic and autoimmune sialadenitis (recurrent allergic, Sjogren's disease and syndrome, etc.);
5. myoepithelial sialadenitis caused by a pathological process, previously designated as a benign lymphoepithelial lesion. The term benign lymphoepithelial lesion was first used by JT Godwin in 1952, replacing the concept of Mikulicz disease;
6. obstructive sialadenitis, which develops when there is difficulty in the outflow of saliva due to obstruction of the excretory duct with a stone (Fig. 5-7) or thickened secretion, as well as due to cicatricial stenosis of the duct. According to the prevalence of the process, they distinguish between focal, diffuse sialadenitis and sialodochitis - inflammation of the excretory duct. The course of the process can be acute or chronic;
7. pneumosialadenitis, which develops when there is air in the gastric tissue in the absence of a bacterial gas-forming infection. Air enters the gland from the oral cavity when the pressure there increases through the duct. Pneumosialadenitis is typical for a number of professions, primarily for glassblowers and musicians playing wind instruments.

Rice. 4.

Post-radiation sialadenitis.

Rice. 5.

Stone of the duct of the submandibular salivary gland.

Rice. 6.

Stone in the parenchyma of the submandibular salivary gland.

Rice. 7.

Stone in the duct of the submandibular salivary gland.

Tumors of the salivary glands

Tumors of the salivary glands are divided into two groups: epithelial and non-epithelial. Epithelial tumors predominate in adults (95%). In children with SG, epithelial and non-epithelial tumors are equally common. In addition to true tumors, processes resembling tumors (tumor-like lesions) develop in the GS.

Among epithelial tumors of the gastrointestinal tract, benign neoplasms are distinguished, as well as malignant ones - carcinomas.

Benign epithelial neoplasms of the stomach include ductal papillomas, adenomas and benign sialoblastoma. SG adenomas are divided into two groups: polymorphic (the most common SG adenoma) and monomorphic (all other) adenomas. Tumors of different structure, origin and prognosis were artificially included in the group of monomorphic adenomas.

Pleomorphic (polymorphic) adenoma (mixed tumor of the gland) is a adenoma of the gland, built from two types of cells: ductal epithelium and myoepithelial cells. Macromorphological picture. The tumor is usually an elastic or firm nodule of lobulated grayish-white tissue, usually partially encapsulated. Typical of a pleomorphic adenoma is the so-called chondroid stroma, resembling hyaline cartilage. Variants of the echographic image of pleomorphic adenomas are presented in Figure 8.

Rice. 8.

Pleomorphic adenoma of the gastrointestinal tract.

Warthin's tumor is an adenolymphoma in which multiple cystic cavities are formed, covered with double-layered epithelium. The papillae protrude into the lumen of the cysts. A pronounced proliferation of lymphoid tissue occurs in the tumor stroma. This tumor almost exclusively develops in the parotid gland.

Other types of benign tumors are less common. These are benign oncocytoma (oxyphilic adenoma), basal cell adenoma, tubular adenoma, benign cystadenoma sialoblastoma.

Among benign primary non-epithelial tumors, the most common are hemangioma, lymphangioma, neurofibroma and lipoma.

Among malignant non-epithelial tumors, malignant lymphomas are more often found (they arise, as a rule, against the background of myoepithelial sialadenitis, Sjögren's disease and syndrome).

Tumor-like lesions of the salivary glands

Rice. 9.

Salivary gland cysts.

1. Salivary gland cysts (mucoceles). There are two types of mucocele of the gland: the retention type (retention cyst of the small gland, formed when saliva is retained in the excretory duct) and the type of interstitial secretion, when, when the wall of the duct is injured, saliva enters directly into the fibrous tissue surrounding the gland. Mucoceles in the floor of the mouth are also called ranulae.
2. Cysts of the excretory ducts of large SGs are pronounced dilatation of the excretory duct due to retention of secretions in it. Blockage of salivary outflow can be caused by various reasons: tumor, stone, thickened mucus, post-inflammatory stenosis, even cicatricial obliteration of the lumen.
3. Sialoadenosis (sialosis) is a non-tumor and non-inflammatory symmetrical increase in SF due to hyperplasia and hypertrophy of secretory cells. The outcome of sialosis is often SG lipomatosis. The process has a chronic relapsing course. Sialosis occurs in a number of diseases and conditions: diabetes mellitus, hypothyroidism, malnutrition, alcoholism, liver cirrhosis, hormonal disorders (hypoestrogenemia), reactions to medications (most often antihypertensive), neurological disorders.

Adenomatoid hyperplasia of small SGs leads to their increase to 0.5-3.0 cm in diameter. The causes of adenomatoid hyperplasia are trauma and prolonged exposure to ionizing radiation.

Oncocytosis is age-related changes in secretory cells and epithelium of the ducts of the gastrointestinal tract. In this case, the SF may slightly increase, but usually their value does not change.

To summarize, I would like to note that ultrasound using Doppler sonography in many of our observations helped to accurately determine the nature of the pathological process in the gastrointestinal tract. However, this diagnostic method does not allow one to unambiguously confirm or refute the malignant nature of the formation of the salivary glands.

Literature

1. Benign and malignant tumors of soft tissues and bones of the face. A.G. Shargorodsky, N.F. Rutsky. M.: GOU VUNMTs, 1999.
2. Topographic anatomy and operative surgery. I.I. Kagan, S.V. Chemezov. M.: GEOTAR-Media, 2011.
3. Salivary glands. Diseases and injuries. V.V. Afanasiev. M.: GEOTAR-Media, 2012.
4. Inflammatory diseases of the tissues of the maxillofacial area and neck. A.G. Shargorodsky. M.: GOU VUNMTs, 2001.

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How to prepare for the procedure

Ultrasound of the salivary glands is an absolutely safe and painless manipulation, for which the patient does not require special preparation. Patients of almost any age tolerate the procedure well, without showing any anxiety before and during its implementation, and therefore it does not require premedication (pre-administration of sedative medications) even in children.

On the eve of the visit to the specialist (about 3-4 hours in advance), the patient is advised to refrain from eating, and immediately before the examination he needs to thoroughly clean the oral cavity.

References

1. Malignant tumors of the salivary glands, Clinical guidelines. Association of Oncologists of Russia, 2022. - 55 p.
2. Balkanov, A.S., Bychenkova, O.A., Sipkin, A.M. and others. Combined treatment of parotid salivary gland cancer. Almanac of Clinical Medicine, 2022. - No. 4. - P. 309-313.
3. Polyakov, V.G., Shishkov, R.V., Ermilova, V.D. and others. Children's Oncology, 2004. - No. 1. - P. 45-47.
4. Carlson, E., Schlieve, T. Salivary Gland Malignancies. Oral and maxillofacial surgery clinics of North America, 2022. - Vol. 31(1). — P. 125-144.

How to do an ultrasound of the salivary gland

The examination can be carried out in 2 ways: from the oral cavity and from the external surface. The procedure does not take much time (it usually takes no more than 20-30 minutes to complete). During an ultrasound scan of the salivary glands, the patient does not feel any pain or other discomfort.

During the examination, the patient takes a supine position, places his head on a specially prepared pillow and tilts it slightly back (or turns it to the left or right, depending on the location of the gland being examined).

If the parotid gland is being examined, the device's sensors are placed on the parotid area. When studying the sublingual and submandibular glands - into the oral cavity (sometimes the extraoral method can be used).

Signs and symptoms of salivary gland cancer

Symptoms of the disease are often caused by damage to important nerves and other structures that pass through or near the salivary glands. Possible signs of cancer include:

• Bumps, lumps, or lumps in the mouth, cheek, jaw, or neck.
• Numbness of part of the face.
• Persistent pain in the mouth, cheek, jaw, ear, or neck.
• Weakness of the muscles on one side of the face.
• Non-healing mouth ulcers.
• Pain when trying to open your mouth wide.
• Outflow of fluid from the ear.
• Changing the size or shape of the left or right sides of the face and neck.
• In the later stages of the disease, problems with swallowing often appear.

Many of the above symptoms may be caused by benign tumors—those that are not life-threatening and do not spread throughout the body—or other conditions. However, if any of them appear, it is necessary to consult a doctor as soon as possible, who will determine the cause of this condition and prescribe treatment.

Ultrasound of the submandibular salivary gland

The norm for an ultrasound examination of the salivary submandibular gland corresponds to the following parameters:

• Fine-grained homogeneous structure.
• The edges of the glands are smooth.
• The excretory duct is well visualized, small in size, without signs of blockage.

Determining the normal size of the submandibular glands is not particularly difficult precisely because of its clear contours. During inflammation (sialoadenitis), the organ increases in size and its edges become blurred.

Treatment

Having established the causes of inflammation of the tongue, the specialist prescribes treatment. In case of inflammation of the salivary glands, the purulent contents are initially removed, then antibacterial agents are injected into the ducts, and the patient is also prescribed antibiotics or sulfonamide drugs orally.

As a rule, therapy is accompanied by rinsing (in each case the doctor selects the optimal solution) and physiotherapy: UHF, Sollux and others. For fever and general malaise, paracetamol or ibuprofen is prescribed.

Surgical treatment methods are used extremely rarely. The operation is performed if there are stones in the duct and they cannot be removed in any other way.

If you experience unpleasant symptoms or discover inflammation or swelling under your tongue, do not look for what it might be. Go to a qualified dentist, he will examine the oral cavity, make a diagnosis, and prescribe adequate therapy. Perhaps pain in the sublingual space is a symptom of another serious disease and consultation with an appropriate specialist will be required.

Monitor the condition of your teeth and mucous membranes, visit the dentist regularly, promptly treat inflammation of the ENT organs and ARVI - such preventive measures will minimize the possibility of inflammation and pain.

Ultrasound of the sublingual salivary gland

Normally, the sublingual salivary gland has smooth, not very clear contours. They have a homogeneous structure, but echogenicity (the ability to reflect ultrasound) may be slightly increased. In the absence of any diseases, the device will not show the ducts of this organ.

The shape of the sublingual salivary glands displayed on the device screen changes depending on where the sensor is placed. When located in the chin area, the glands have oval contours. If the device is applied parallel to the body of the lower jaw, the glands will be slightly elongated.

Norm

The parotid gland is normally located symmetrically opposite and is visualized in the form of capsules. On ultrasound, the anterior surface is normally clearly visible, the deep zones are not visible, and the posterior sections have a weak outline. The structure of a healthy organ should be homogeneous and fine-grained. The submandibular gland is normally fine-grained on ultrasound, uniformly structured, with smooth edges, the outlet of the ducts is clearly visible, the size is small, and has no signs of blockage. Determining the size of a healthy submandibular gland on an ultrasound is not difficult due to its well-defined contours. And during inflammatory processes, the organ enlarges, and the edges lose their clarity. The sublingual gland on ultrasound has a weakly defined smooth outline, the structure is homogeneous, and the echogenicity is slightly increased. Normally, the ducts are not visible. The shape of the glands changes depending on the viewing angle. In the chin area, an oval shape is visualized; in a position parallel to the body of the lower jaw, it is slightly elongated. The ducts of the parotid salivary glands are not visible in a healthy state. They can only be detected if pathology is present.