Benign mixed tumor. Mixed tumor of the salivary glands. Symptoms of a mixed salivary gland tumor

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Salivary gland tumors

Clinical approach. The examination of children with tumor-like formations of the salivary gland should be approached very methodically. First of all, the clinician must determine whether this formation is neoplastic or inflammatory. Tenderness, recent appearance of a tumor, and fever suggest inflammation.

With mumps (mumps), the parotid gland is usually diffusely enlarged, painful, and there are signs of intoxication and hyperamylasemia. Facial nerve paralysis, rapid growth, pain and immobility of the formation may indicate a malignant process. Saliva may be detected by cannulation of the duct or aspiration tissue biopsy with cytological examination. In 2/3 of cases of malignant lesions, saliva is detected during cytological examination.

Ultrasound is extremely important in differential diagnosis; CT and MRI can also be useful. The anatomy of the facial nerve and its relationship to the tumor is best demonstrated by MRI.

Any, even the slightest suspicion of a malignant process is an indication for a biopsy of the salivary gland. Incisional biopsy is contraindicated except in cases of severe lesions with unresectable malignancy. Fine needle aspiration biopsy has been used with some success in adults, but its effectiveness in children has not yet been clearly established. An excisional biopsy with a wide margin is preferred.

When the parotid gland is affected, the method of choice is superficial lobectomy of the gland with preservation of the facial nerve. Frozen section data should not be used as a basis for determining the extent of resection because this method may produce erroneous results.

Benign tumors. The most common benign tumor of the salivary glands in children is angioma and its varieties, and in infants, hemangioendothelioma is the most common tumor of the parotid gland. Although at birth these tumors are usually not visible and not determined, the correct diagnosis is usually established in the first 6 months of life.

Tumors are much more common in girls. Clinically, they are mobile elastic formations of the parotid gland, often with a bluish discoloration of the skin over them. The tumor may be lukewarm to the touch. These benign tumors are usually painless and can progressively enlarge as the child grows. Sometimes the tumor grows quickly in the first few weeks after birth. The diagnosis is usually obvious simply from examination and physical examination.

Although surgical excision of the tumor is traditionally recommended, there is a high probability (90%) of spontaneous regression. These neoplasms are almost always benign in children, including infants. If the tumor does not disappear spontaneously by the time the child is supposed to go to school, then this is an indication for surgery.

Rare neoplasms of the parotid gland that occur at birth or in the first months of life include embryomas. This encapsulated tumor is often located above the angle of the mandible. Although in most cases the tumor is benign, in 25% of cases malignancy is noted both histologically and clinically.

Lymphangioma (cystic hygroma) can also affect the parotid and minor salivary glands in children. Unlike other neoplasms, it occurs quite often. These tumors are discussed in detail in the next chapter (73). Juxtaparoid (periparotid) or intraparotid lymphangiomas occur rarely. These are usually mixed neoplasms with lymphoid and vascular components. They may spontaneously undergo involution, but if this does not occur, then surgical removal is indicated. During the initial intervention, it is important to remove the tumor completely, while trying to keep the facial nerve and its branches intact. However, sometimes repeat resection may be required. The likelihood of treatment success decreases with each new relapse.

Pleomorphic adenoma (mixed tumor) is the most common epithelial tumor of the salivary glands, both in children and adults. Boys and girls are affected with equal frequency. The tumor occurs mainly between the ages of 10 and 13 years. It is a small, dense, well-demarcated formation, palpable in the parotid gland.

There are reports of an increase in the incidence of this tumor in children exposed to ionizing radiation, as well as in children whose parents were in the area of ​​the atomic bomb explosion. The treatment of choice is superficial parotidectomy with preservation of the facial nerve. Some clinicians recommend an excisional biopsy if there is no evidence of malignancy. Many studies have reported a significant incidence of local recurrence.

Adenolymphoma (Warthin's tumor) occurs in 1% of cases among all tumors of the salivary glands, while at the same time it ranks second in frequency among benign epithelial tumors of the salivary glands. In boys, this tumor occurs more often, combined with Mikulicz's disease (keratoconjunctivitis with xerostomia, structural abnormalities of the lacrimal glands and benign lymphoepithelial tumor). Treatment consists of surgical removal of the tumor.

Malignant tumors. Most malignant tumors of the salivary glands are localized in the parotid gland. The prognosis is somewhat better than for tumors of the minor salivary glands. Depending on the histological picture, several grades of malignant neoplasms of the salivary glands are distinguished: grade 1 (well differentiated), grade II (moderate degree of differentiation) and grade III (poorly differentiated).

The histological type of the tumor allows one to predict the clinical course of mucoepidermoid carcinomas, but in acinar cell carcinoma the histological structure has no prognostic value. Most of these tumors have a low or moderate degree of differentiation.

Mucoepithelial carcinoma is the most common primary malignant tumor of the salivary glands in both adults and children. This tumor can be mistaken for a chronic inflammatory process, since it is often combined with fibrocystic changes and chronic inflammation. The extent of the primary lesion directly determines the likelihood of metastasis to the cervical lymph nodes and the risk of recurrence after resection. Young children have a high tendency to malignancy.

Treatment consists of total or superficial parotidectomy, depending on the nature of the tumor. For small, poorly differentiated tumors and for some intermediate-grade tumors limited to the superficial lobe, a superficial parotidectomy may be performed.

Local lymph nodes are biopsied with frozen section examination. If damage to the lymph nodes of the neck is detected, then radical removal of them is carried out either simultaneously or, alternatively, later. One study noted that in 15% of cases there were metastases to the cervical lymph nodes, but in none of these observations were metastases clinically determined.

The effectiveness of chemotherapy and radiation therapy for high-grade lesions is difficult to assess due to the relative rarity of these tumors. Relapses usually occur within a year. In general, 90% of children with grade I and II mucoepidermoid carcinoma live a long time. Survival rate for grade III tumors is below 50%

Adenocarcinoma is the second most common type of malignant neoplasm of the salivary glands in children. The undifferentiated or solid variant usually occurs in preschool age and is often extremely aggressive. Facial paralysis, pain, and rapid tumor enlargement are signs of an anaplastic or undifferentiated tumor. Treatment should be combined, including surgical removal of the tumor, chemotherapy and radiation therapy. The results vary.

Acinic cell carcinoma is the third most common malignant tumor of the parotid gland in children, usually occurring as a painless mass between 10 and 15 years of age. The prognosis is relatively favorable.139
Nonepithelial round or spindle cell tumors of the salivary glands sometimes cause diagnostic difficulties. One study reported that 5% of 202 rhabdomyosarcomas were found in the parotid and other salivary glands.

K.U. Ashcraft, T.M. Holder

"Mixed" tumor is the most common neoplasm of the salivary glands. It is localized mainly in the parotid salivary gland, much less often in the submandibular and minor salivary glands, and very rarely in the sublingual. The tumor has an extremely diverse microscopic structure: along with epithelial structures, it contains fibrous, myxomatous, fatty, chondro-like, muscle and even bone formations, which do not have clear boundaries and gradually transform into one another.

"Mixed" tumor It occurs in people of all ages, more often after 30 years, mainly in women. In the vast majority of cases, it has a benign clinical course, prone to relapses and sometimes to malignancy. A “mixed” tumor develops slowly and painlessly. Only in some cases is there rapid growth and in isolated cases the appearance of minor pain of an unspecified nature in the area of ​​its location.

Clinically “mixed” tumor appears to be a dense or densely elastic, mobile, painless formation ranging from 3 to 5 cm or more in diameter, round or ovoid in shape with a smooth or coarsely lumpy surface, which is well demarcated from the adjacent tissues of the gland. The skin over the tumor, as a rule, is not changed. With small tumors they easily gather into a fold. The tumor itself is usually mobile, although in depth it is fused with the underlying tissues. When the tumor size is significant, it becomes inactive, the skin over it becomes stretched and thins.

There is no damage to the facial nerve. Enlargement of regional lymph nodes is not observed. Opening the mouth is not difficult.

When the tumor is located on the palate, the mucous membrane covering it also does not change. And only when the tumor is large, it becomes stretched and thinned and has a clear pattern of a network of blood vessels. Ulceration of the tumor is usually not observed.

The sialogram shows displacement of the gland ducts by the tumor, and according to the location of the tumor, a rounded clearing zone can be traced. Repressed ducts, as a rule, have no changes. Such a picture only determines the benign quality of the tumor, but does not make it possible to judge its morphological structure.

The diagnosis is usually made on the basis of histological examination. On histological examination parenchyma of a “mixed” tumor appears in the form of fields, cords and cells of densely lying epithelial cells. There are strands and accumulations of multilayered flat non-keratinizing and keratinizing epithelium, sometimes with the presence of horny “pearls”. In the tumor tissue, glandular ducts lined with columnar epithelium and having a slit-like or cystic-widened lumen are also revealed. Epithelial structures gradually transform into myxoma-like formations. In this case, loosely lying stellate cells appear immersed in a basophilic mucus-like substance. Myxoma-like tumor formations gradually transform into chondro-like structures similar to hyaline cartilage.

The tumor stroma consists of either narrow or wide layers of fibrous connective tissue, poor in blood vessels. Sometimes small areas of adipose tissue and focal accumulations of lymphocytes are included in the stroma; there are also foci of calcification, and occasionally small areas of bone tissue.

Mixed tumor

A special group of benign neoplasms consists of tumors of the salivary glands - the so-called mixed tumors. These tumors received this name as a result of the presence of tissues of both epithelial and connective nature. Typically, a mixed tumor contains fatty, myxomatous, cartilage, muscle, glandular and even bone tissue.

Most often, mixed tumors affect the parotid salivary glands, although they are sometimes found in other parts of the maxillofacial region, but only where there are glandular elements (submandibular salivary gland, palate, cheeks, etc.).

The cause of the occurrence of mixed tumors is seen in the delay of embryonic cells, the development and growth of which suddenly occur under the influence of currently unknown causes. Some authors reject this opinion. Others believe that all tissue varieties that make up the stroma of a mixed tumor are the product of modification of the epithelium of the salivary or mucous gland.

A characteristic feature of a mixed tumor is that it sometimes does not show signs of growth for a long time (years or even decades). However, at some point, the tumor suddenly begins to grow rapidly, which acquires the features of a malignant one (proliferation of its membrane and surrounding tissues, metastasis of tumor cells). Depending on the predominance of connective tissue or epithelial elements, the tumor develops as a sarcoma or cancer.

A mixed tumor is also sometimes characterized by the presence of several rudiments (their number can reach several dozen). This sometimes explains the growth of the tumor after careful removal of it along with the membrane. Given this, it is hardly correct to call such cases “relapse.” Obviously, trauma to the “dormant” rudiments during removal of a mixed tumor is an impetus for their growth and development.

Clinically, a mixed tumor in 80-90% of cases is found in the area of ​​the parotid salivary glands (Fig. 123).

A tumor that has retained the features of a benign tumor is defined as a dense, with clear contours, painless and easily removable neoplasm. More often, patients are found to have a mixed tumor with a diameter of 1 to 3-4 cm. However, a mixed tumor can be much larger, reaching the size of a fist and even a child’s head.

The growth of a mixed tumor usually does not cause pain, so patients often consult a doctor due to the appearance of facial asymmetry. However, a mixed tumor can also affect the areas of the hard and soft palate, where even if it is small in size it can cause difficulty speaking and eating (Fig. 124).

Unlike atheroma, a mixed tumor is not associated with the skin, and compared to lipoma it has clearer contours. Reliable information about the nature of the tumor can be obtained after a puncture biopsy. Considering the possibility of malignancy of a mixed tumor, in cases where there is no mobility, which indicates the presence of infiltrative growth, the puncture must be performed after 2-3 sessions of radiation therapy.

Treatment is surgical. If there is no suspicion of malignancy, the tumor is removed without prior radiation therapy, usually with partial resection of the parotid or removal of the submandibular salivary gland, depending on the location of the tumor. Postoperative treatment is determined depending on the results of histological examination. However, some oncologists consider radiation therapy in the pre- and postoperative period to be mandatory.

When a mixed tumor becomes malignant, the scope of surgical intervention expands. If the parotid salivary gland is damaged, the entire gland is extirpated; if the hard palate is involved in the process, resection (full or partial) of the upper jaw is performed. Patients who are found to have a mixed tumor should be consulted by an oncologist and placed under special care.

The term “mixed tumors” reflects a previously existing understanding of the features of the histogenesis of these neoplasms. In the present time, this term is used more often to characterize the heterogeneity and complexity of their structure than to characterize histogenesis, which still seems controversial. Most researchers tend to consider Mixed tumors to be epithelial, with the leading role in the formation of mesenchymal-like areas assigned to myoepithelial cells (myoepithelial cells). In this regard, it is believed that the essence of this neoplasm is more fully reflected by the term “pleomorphic adenoma” recommended by WHO.

Mixed tumors account for 50-70% of epithelial neoplasms of large and 20-55% of tumors of minor salivary glands. From the large salivary glands Mixed tumors are more often found in the parotid glands, from the small ones - in the palatine salivary glands. Multiple tumors of more than one salivary gland are rarely found. Mixed tumors very rarely occur in the lacrimal, sweat glands, and mucous glands of the respiratory tract. Mixed tumors are more common in women aged 50-60 years. They are extremely rare in newborns and rarely in children.

Macroscopically, the tumor node is clearly defined, often round in shape, dense or densely elastic in consistency, often lobulated in appearance. As it grows, the capsule of the node becomes more pronounced. On section, the tumor tissue is whitish in color, often with characteristic cartilaginous, translucent and mucous areas. On microscopic examination, mixed tumors are heterogeneous and are represented by a combination of epithelial and mesenchymal-like areas. Epithelial regions consist of epithelial and myoepithelial cells. Epithelial cells that form glandular, tubular, two-layer structures can be small, cubic in shape, with a small amount of cytoplasm, or larger, cylindrical in shape, with eosinophilic granular cytoplasm, that is, they are characterized by signs of differentiation towards the epithelium of various parts of the salivary gland. Epithelial elements are located in the form of nests and cords anastomosing among themselves; in glandular structures they are often surrounded by zones of small elongated or rather large light myoepithelial cells. The latter form substantial fields in some areas. Epithelial areas without clear boundaries become myxomatous and chondroid. Myxomatous areas are formed by stellate cells located in the mucous substance, chondroid areas are formed by isolated round cells in the chondroid matrix.

Clinical, the course is usually slow. The tumor sometimes reaches a significant size and is painless. The skin and mucous membrane over the tumor are preserved; the skin over the node is easily displaced. In some cases, a period of slow growth is followed by a phase of rapid growth of the tumor.

In diagnosis, puncture biopsy followed by cytological examination is important. X-ray examination (see full body of knowledge: Sialography) allows you to clarify the nature of the lesion and its topography.

Treatment is surgical. When small mixed tumors are localized (up to 20 mm in diameter) in the lower, upper poles or posterior edge, as well as in the pharyngeal process (mandibular process, or the deep part of the parotid gland), resection of the gland is possible.

Subtotal resection of the parotid gland in the plane of the branches of the facial nerve is indicated for a tumor located deep within the gland or occupying a significant portion of its surface part. Parotidectomy with preservation of the branches of the facial nerve (see full body of knowledge: Parotid gland, tumors) is performed for large mixed tumors, tumors of the pharyngeal process (with the exception of large neoplasms with parapharyngeal growth). Resection of the pharyngeal process of the parotid gland using an external submandibular approach is indicated for mixed tumors of the pharyngeal process protruding into the cavity of the oropharynx, nasopharynx and oral cavity.

Mixed tumor of the salivary glands

The name mixed tumor is due to the variety of tissues included in the structure of this tumor, which is localized in the large and small salivary glands.

Of the large salivary glands, a mixed tumor primarily affects the parotid glands, then the submandibular glands, and finally the sublingual glands.

In addition to large ones, a mixed tumor can be localized in minor salivary glands, located in many places in the oral mucosa: in the area of ​​the hard and soft palate, cheeks, tongue, at the bottom of the mouth, and also in the lips.

Among patients with mixed tumors, females predominate. This tumor is observed at all ages. Congenital mixed tumors of the parotid and submandibular salivary glands have been described.

We examined the surgical material in the amount of 134 cases, in which the diagnosis of “mixed tumor” was histologically confirmed. This included peculiar variants of salivary gland tumors, also of epithelial origin: cylindroma and mucoepidermoid tumor.

Of the 134 observations, mixed tumors were in 71 females and 63 in males. By age, patients were distributed as follows: 10-20 years - 12 patients, 21-30 years - 27, 31-40 years - 20, 41-50 years - 41, 51-60 years - 19, 61-70 years - 13, over 70 years old - 2 patients.

Macroscopically, the size of a mixed tumor can be the size of a hazelnut or larger, sometimes reaching larger sizes. K.K. Alkalaev and N.V. Garifulina described a mixed tumor of the sublingual salivary gland measuring 5 X 19 X 17 cm. A mixed tumor, as a rule, has a capsule delimiting it from the surrounding tissues. The surface of the tumor is often lumpy, sometimes the tumor consists of nodes fused together. Its consistency is usually dense, whitish-gray or gray-reddish when cut. Hemorrhages, softening and cysts may be observed in the tumor.

The histological structure of a typical mixed tumor is characterized by the presence of complexes of epithelial cells of fibrous connective, often hyalinized, mucous and cartilaginous tissue (Fig. 49).

The epithelial areas of the tumor consist of uniform, polygonal small cells with round, small, chromatin-rich nuclei. The epithelium is located in the form of trabecular complexes or like glandular structures. In a mixed tumor, the amount of mucous and cartilage tissue varies, or these tissues may be absent.

In some cases, large areas of cartilage tissue, consisting of a homogeneous pink or bluish-tinged main substance (when stained with hematoxylin-eosin) and cartilage cells surrounded by a capsule, are located directly next to the transitional type epithelium.

The mucous substance with characteristic stellate cells in a mixed tumor can be in small quantities or occupy large areas, also located directly next to or between the epithelial cells of the tumor.

The appearance of mucous tissue in mixed tumors is associated with mucous degeneration of the epithelium and with the mucous transformation of the interstitial mesenchymal tissue of the tumor, as shown by relevant histochemical studies. Sometimes a mixed tumor contains islands of adipose tissue.

In addition to this typical structure of a mixed tumor, it may exhibit peculiar deviations in the structure. Thus, in epithelial complexes among polygonal cells there may be areas of squamous epithelium, sometimes with keratinization, as well as multiple small petrifications, usually round in shape.

Some mixed tumors have significantly elongated epithelial cells connected to each other by rather long processes. In cases where the tumor exhibits pronounced hyalinosis of the main substance, the epithelial cells are located in the form of a delicate network among the hyalinized tissue.