X-ray signs of benign tumors

X-ray diagnostics of benign odontogenic tumors

A distinction is made between odontogenic and non-odontogenic benign tumors of the jaws. Among odontogenic neoplasms, odontomas and ameloblastomas are most common.

Odontoma is a benign tumor consisting of various dental tissues (enamel, dentin, cement, pulp, fibrous tissue), developing mainly in people under 20 years of age. Patients usually come for an X-ray examination with complaints of delayed eruption of permanent teeth. Sometimes odontomas are discovered accidentally during an X-ray examination for another reason.

According to the WHO classification, a distinction is made between composite and complex odontoma. A composite odontoma contains all the tissues of the tooth at different stages of their formation, while a complex odontoma contains unformed tissues of the tooth and a soft tissue component. Composite odontomas are localized in the upper jaw in the frontal section in most cases, while complex odontomas are located mainly in the lower jaw in the area of the first and second molars.

On radiographs, odontomas are highly intense and consist of multiple foci of irregular calcification, tooth-like fragments, or teeth at varying stages of formation.

The contours of the odontoma are clear, sometimes wavy, scalloped, and a strip of enlightenment is visible along the periphery, due to the presence of a capsule. When the odontoma suppurates, the contours of the surrounding tissue become unclear, and fistulous tracts may appear.

Odontomas grow expansively, causing displacement, thinning of the cortical plates of the jaw, swelling, facial asymmetry, and tend to erupt into the oral cavity.

Ameloblastoma (adamantinoma) is a benign tumor that develops from proliferating odontogenic epithelium located in connective tissue. It is usually diagnosed in the 4th-5th decade of life. In 80% of cases, ameloblastoma develops on the lower jaw, in 20% - on the upper jaw. On the lower jaw, in 70% of cases, it is localized in the area of the molars and branches, in 20% - premolars and in 10% - in the area of the incisors.

On radiographs, ameloblastoma looks like a polycystic (multi-chamber) formation or a single cystic cavity. Polycystic ameloblastoma resembles a picture of soap bubbles: it consists of multiple foci of bone tissue destruction of a round and oval shape, separated from each other by bone partitions.

The multi-chambered appearance is sometimes due to the tumor protruding into the spongy and cortical parts of the bone to varying depths.

Ameloblastoma causes deformation of the lower jaw due to its swelling, while in some areas of the jaw there is a displacement, thinning and interruption of the cortical plates. The teeth located in the tumor growth zone are displaced, their roots are sometimes resorbed. If there is no secondary inflammatory component, then the periosteum reaction is absent. The impression of interruption of the cortical plate of the jaw can be caused not only by destruction, but also by its displacement.

The tumor may contain one or more unerupted teeth. The mandibular canal is displaced downwards.

Differential diagnosis with other cystic lesions of the jaws, in particular with osteoclastoma, is possible only on the basis of the results of histological examination.

Of the non-odontogenic tumors, the most common are osteomas, osteoclastomas, and hemangiomas.

Osteoma is a mature benign tumor that develops from differentiated bone tissue. Depending on the structural features, there are compact, spongy and mixed osteomas.

Most often, osteomas are localized in the paranasal sinuses, usually in the frontal and ethmoid bones and on the lingual surface of the mandible.

On radiographs, peripherally located osteomas look like a round bone formation on a wide base or narrow stalk, with clear, even contours emanating from the bone. On the walls of the frontal and maxillary sinuses, they are determined as dense bone masses, and can grow into adjacent areas.

Multiple osteomas of the upper and lower jaws are sometimes combined with supernumerary teeth and polyposis of the colon.

X-ray diagnostics of osteomas in most cases does not cause difficulties. When they are located in the posterior sections of the hard palate and on the lingual surface of the anterior sections of the lower jaw, difficulties arise in differential diagnostics from the palatine and mandibular tubercles (torus palatinus and torus mandibularis).

Osteoclastoma (osteoblastoclastoma, giant cell tumor). Osteoclastomas are localized in the lower jaw much more often (in 10% of all cases) than in other parts of the skeleton. They are most often diagnosed in the 3rd decade of life; osteoclastomas are characterized by relatively slow growth.

Depending on the characteristics of the radiographic picture, cellular, cystic and lytic variants of osteoclastoma are distinguished. In the cellular variant, against the background of foci of destruction, a cellular-trabecular structure is revealed - a large number of cavities of various shapes and sizes, separated from each other by thin bone partitions.

The cystic form is represented by a cystic cavity of a round or oval shape with clear contours. As the tumor grows, it causes swelling and thinning of the cortical plates of the jaw.

In the lytic variant, the diagnosis of which is associated with great difficulties, osteoclastoma is defined as a single marginal focus of destruction, sometimes uneven in intensity, with fairly clear contours.

The contours of osteoclastomas at the border with unaffected bone are visible, although quite well, but not as clearly as with radicular cysts. Reactive osteosclerosis at the edges of the tumor is absent.

As the osteoclastoma grows, displacement, thinning and discontinuity of the cortex, swelling of the jaw are observed. Discontinuity of the cortex and growth into the perimaxillary soft tissues and under the mucous membrane are not evidence of its aggressiveness or malignancy.

The neoplasm causes jaw deformation, root resorption, displacement and mobility of teeth. In the upper jaw, the tumor can grow into the maxillary sinus, orbit, nasal cavity, causing facial deformation.

In the upper jaw, osteoclastoma affects mainly the alveolar process and is represented by foci of destruction of irregular shape with polycyclic contours. Leading to protrusion, thinning and interruption of the cortical plate of the jaw, the tumor grows into the perimaxillary soft tissues, causing deformation of the face.

Since swelling occurs predominantly in the buccal-lingual direction, radiographs of the lower jaw in axial projection are informative for assessing the condition of the cortical plates.

Osteoclastomas also include giant cell epulis localized on the alveolar process, which, as they grow, cause the formation of marginal bone destruction.

Osteoclastoma should be distinguished from keratocyst, ameloblastoma, myxoma, fibrous dysplasia, intraosseous hemangiomas. The radiographic picture of the lytic form may resemble that of osteogenic sarcoma. Differential diagnostics, especially for tumors localized in the upper jaw, is possible only on the basis of histological examination results.

After radiation therapy, there is an increase in reparative processes in the form of thickening of the cortical plates of the jaw and bone beams. At the same time, the cellular and cystic forms can turn into lytic, and even the growth rate accelerates.

Hemangioma. Vascular tumors - hemangiomas arise in the soft tissues around the jaw or inside the bone and consist of proliferating blood vessels. The lower jaw is most often affected, and there are more women among patients. Hemangiomas are most often detected between the ages of 10 and 20.

Some authors classify hemangioma as a dysembryoblastic tumor that occurs as a result of a congenital vascular malformation. In children of the first year of life, congenital hemangiomas sometimes undergo regression. In hemangiomas of the perimaxillary soft tissues, shadows of phleboliths and angioliths with a diameter of 5-6 mm are sometimes visible on images. Hemangiomas that occur in the perimaxillary soft tissues, exerting pressure on the bone, cause a marginal saucer-shaped defect. In children, hemangiomas disrupt the development of the jaws and tooth rudiments.

The radiographic picture of jaw hemangiomas is extremely polymorphic: in the form of a single cystic cavity with clear or unclear contours or multiple foci of bone tissue destruction of various shapes and sizes (the “soap bubble” picture).

When hemangiomas develop from the vessels of the mandibular canal, a rarefaction center of a round or oval shape is detected along the canal.

Hemangioma can cause thickening of the bone trabeculae, as if in the form of rays diverging from one center (the “wheel with spokes” picture).

Intraosseous hemangiomas, as they grow, cause displacement and thinning of the cortical plates, and in some cases can lead to their destruction. Periosteal layers are usually absent. Teeth located in the tumor growth zone are mobile, their roots are resorbed. When pressing on the crown, the teeth "sink", and after the pressure is stopped, they take their previous position.

When removing teeth located in the area of an arterial hemangioma, profuse bleeding may occur, which can be life-threatening.

Fibrous dysplasia is a tumor-like disorder. The pathological process is based on a congenital defect of bone formation that occurs both in the embryonic and postnatal periods and is characterized by a disruption in the transition of mesenchymal tissue and its derivatives - connective and cartilaginous tissue - into bone. The disease is most often detected during the period of active growth of the jaw and facial bones - at the age of 7 to 12 years.

Depending on the involvement of one or more bones of the skeleton, mono- and polyostotic forms are distinguished. Not only the bones of the facial and cranial skull are affected, but also other parts of the skeleton. The polyostotic form of the disease is often combined with various endocrine disorders.

The radiographic picture of fibrous dysplasia is varied and reflects the pathological anatomical nature of the process. At an early stage of the process development, a focus of bone tissue rarefaction with clear or unclear contours is determined.

The jaw lesions are more often monoosseous. On the lower jaw, the rarefaction area, usually located in the thickness, has an oval or elliptical shape. The upper jaw is affected somewhat more often than the lower jaw, the eye socket is involved in the process, obliteration of the maxillary sinus may occur. Facial asymmetry increases, the formation and eruption of teeth may be disrupted, and they may shift. Root resorption is possible, but the teeth remain immobile. Sometimes the closing cortical plates of the sockets in the affected area are absent. Deformation of the alveolar process occurs mainly in the buccal-lingual direction. An increase in the jaw is sometimes accompanied by pain, which allows one to suspect chronic osteomyelitis.

As the osteoid tissue matures, foci of sclerosis appear, initially usually along the periphery of the rarefaction area. Later, calcification phenomena increase, its foci merge and are determined on the radiograph as areas of high or medium intensity compaction (ground glass pattern), without clear boundaries passing into the surrounding bone.

Sometimes the increase in facial asymmetry stops only after 20 years (at the time of puberty and the cessation of bone growth).

Albright syndrome includes a triad of symptoms: single or multiple foci of fibrous dysplasia in bones, premature puberty in girls, and skin pigmentation. The foci increase in size as the child grows, and then stabilize. The radiographic picture is the same as with fibrous dysplasia.

Cherubism is a specific form of dysplasia that affects only the facial skull and is hereditary. The disease progresses slowly and painlessly between the ages of 2 and 20. The lower (mainly the areas of the angles and branches) and upper (the bottom of the orbit, the tubercle) jaws are affected, with the eyeballs shifting upward, which gives the child's face a specific expression ("cherub face"). The coronoid processes of the lower jaw are usually not involved in the pathological process.

The disease begins at the age of 1-2 years, it is diagnosed at 3-5 years; then it progresses, and by the age of 30 the patient's condition stabilizes. The face acquires normal contours. Boys are more often affected. The lesion consists of vascularized proliferating fibrous tissue containing a large number of multinucleated giant cells. The course of the disease is usually painless. The bone is swollen due to the formation of multiple cystic cavities of various shapes and sizes, the cortex is thinned and interrupted in some areas. A monocystic form of the lesion is also encountered. Various anomalies in the development of teeth are noted (dystopia and retention, disruption of the formation of tooth rudiments, root resorption).