Вінницький національний медичний університет ім. М.І. …



Benign and malignant tumors of the soft tissues and facial bones; their classification, etiology, pathogenesis, clinics, treatment, complications. Methods for primary management of the facial defects.

Tumors and Tumorlike Lesions of the soft tissues.

Epidermoid and dermoid cysts

An epidermoid cyst is a cyst lined by epidermis without the adnexal structures in the fibrous wall that a dermoid cyst has. An epidermoid cyst may result from traumatic implantation of epithelial cells into surface epithelium, whereas in a dermoid cyst entrapment of epithelium during the embryologic phase seems to be the most likely explanation. Both the epidermoid and dermoid cysts rarely occur in the oral cavity and are even rarer in the oropharynx. Epidermoid and dermoid cysts may occur in the floor of the mouth, the lips, and the cheek mucosa. Just a few cases of lingual involvement have been reported. The clinical aspect is not characteristic and merely consists of a cystic swelling. Stratified squamous epithelium without adnexal structures lines an epidermoid cyst. When adnexal structures (such as sebaceous glands) exist, a diagnosis of dermoid cyst can be made. In most instances epidermoid and dermoid cysts can be enucleated. Recurrence is rare.

Fibroma

Almost all lesions in the oral cavity that are called fibromas are not true neoplasms,

but merely fibrous overgrowths caused by chronic irritation. Many authors therefore prefer the term fibroepithelial polyp or fibrous hyperplasia for this type of lesion. They rarely occur before the fourth decade and show no preference for either sex. Fibroma has a smooth overlying mucosa and is often pedunculated. The size may vary from a few millimeters up to some centimeters. The consistency may vary from soft and myxomatous to firm and elastic. A fibroma is asymptomatic and can be located at all sites of the oral and oropharyngeal mucosa. The microscopic picture may show a collagenous stroma and a varying number of inflammatory cells. The fibroblasts may have a giant cell appearance, justifying in some cases the term giant cell fibroma, which does not have any clinical implication. A fibroma is not demarcated or encapsulated. Vascularity may be scarce or very abundant. In the latter case it may be difficult to differentiate the lesion either from a hemangioma with secondary inflammatory signs or from a pyogenic granuloma. Treatment consists of conservative excision. At the same time any possible irritating factors should be removed. Recurrences are exceptional.

Hemangioma

A hemangioma is a benign lesion of blood vessels or vascular elements. The majority of oral and oropharyngeal hemangiomas seem to be of a developmental nature. In some instances lesions are probably a mixture of hemangioma and lymphangioma, leading to the term angiomatosis. In rare instances a hemangioma is located within the jawbones. Hemangiomas of the oral cavity are often present at birth or shortly thereafter. They have a strong preference for occurrence in the tongue and the floor of the mouth. A hemangioma of the tongue may affect just a part of the tongue or the entire tongue, producing macroglossia. The color of a hemangioma may vary from bluish to purple or fiery red. The texture of the mucosa may be more or less unchanged, showing only an increased vascularity on the surface; in other cases, however, there is a pebbly appearance. Pain is not a prominent feature, except in cases of traumatization or secondary inflammation. In severe cases loss of tongue mobility may occur. Bleeding, either spontaneously or from mechanical irritation, can be a serious problem. Angiography may be an aid in diagnosing a hemangioma. A hemangioma may histologically consist of numerous irregular, blood-filled spaces, lined by endothelial cells and surrounded by connective tissue. When a large number of proliferating endothelial cells line small capillaries, the lesion is referred to as a capillary hemangioma. In the case of large dilated blood sinuses, the term cavernous hemangioma is applied. When hemangiomas undergo regression, extensive sclerosis can occur, sometimes followed by calcification. Such concretions are called phleboliths. The majority of hemangiomas do not require treatment and regress spontaneously during childhood. Therapeutic management of a large, persisting, or even growing hemangioma is a difficult problem. A conservative approach seems justified: that is, managing only the areas that produce bleeding. In large, diffuse lesions the use of cryosurgery or CO2 laser therapy does not seem to be effective. Injection of sclerosing agents has been advocated in the past but has not been shown to be effective. The technique of selective percutaneous embolization before surgery has emerged as a valuable adjunct to surgery in the management of such lesions.

Keratoacanthoma

A keratoacanthoma, also called molluscum sebaceum, is a benign cutaneous lesion that is believed to arise from hair follicles. Its etiology is unknown. Men are affected twice as often as women. A keratoacanthoma is usually a solitary and rapidly growing lesion. It appears as a well-circumscribed, slightly elevated lesion that rarely measures more than 1 cm. Centrally a crateriform excavation can be seen with slightly indurated borders. Clinically the lesion may mimic a squamous cell carcinoma. In most cases, however, spontaneous regression occurs, usually within a few months. Occurrence on the lower lip is not uncommon; intraoral and oropharyngeal locations are exceptional. Histologic examination of a keratoacanthoma shows hyperplastic epithelium with carcinoma-like features. In fact, no distinct histologic features seem to be available that can in every case histologically substantiate the diagnosis.

Lipoma.

A lipoma is a benign neoplasm composed of fat cells. Its cause is unknown. Lipoma appears as a sessile, soft, and asymptomatic swelling. When it is located superficially, a yellowish texture can be seen. In rare instances bilateral or multiple occurrence has been reported. Histologic examination of a lipoma shows a well-delineated mass of lobules of fat cells with fibrous septa interspersed between them. When fibrous tissue is a substantial part of a lipom, the term fibrolipoma can be applied. When vascularity is a prominent feature, the term angiolipoma is used. Surgical removal is the treatment of choice. Recurrences have not been reported.

Lymphangioma

A lymphangioma is a benign lesion characterized by proliferation of lymphatic vessels. It is a hamartoma rather than a neoplasm. In some cases making the distinction between a lymphangioma and hemangioma is difficult, in which case the term angiomatosis may be used. Occurrence in the oral cavity and oropharynx is rather rare, the tongue being the usual site. The size may vary from pinhead to massive dimensions. The typical lymphangioma is characterized by irregural nodularity of the mucosa, with gray and pink, grapelike projections. Histologically, endothelium-lined spaces are found in the connective tissue. No true encapsulation occurs and quite often the proliferation of lymphatic vessels spreads diffusely into the surrounding soft tissues. During infectious episodes the combined use of corticosteroids and antibiotics may be required. Small lesions can be excised. With extensive, symptomatic lymphangiomas surgical removal of the bulk of the lesion seems to be the only possible treatment. Complete surgical excision is difficult, particularly in the mouth, because of the multiple fingerlike projections extending into the adjacent tissues.

Schwannoma (neurilemmoma)

A schwannoma is a benign neurogenic neoplasm composed of Schwann's cells.

The tumor may occur at all ages and does not show a preference for men or women.-

A schwannoma is a slowly growing, rather circumscribed, submucosally located tumor that may be painful. No characteristic clinical features appear. It may occur at any site in the oral cavity and rarely involves the oropharynx. Histologically, one sees an encapsulated tumor composed of two cell types, the socalled Antoni type A and Antoni type B cells. Management consists of conservative surgical removal

Neurofibroma A neurofibroma is, like a schwannoma, derived from sheath cells. It actually may represent in many instances a hamartoma or a reactive process rather than a eoplasm. A neurofibroma is asymptomatic and rarely occurs as a single lesion. Most often neurofibromas are part of von Recklinghausen's disease. Quite often the tongue is involved, in some cases resulting in unilateral macroglossia. Also the possibility of hereditary neuropolyendocrine syndrome - consisting of mucosal neuromas, pheochromocytoma of the adrenal glands, and medullary thyroid carcinoma - should be taken into account. In general, the mucosal neuromas in that syndrome are already present at childhood, being the first manifestation of the syndrome. In contrast to the schwannoma, a neurofibroma is not encapsulated. With a single neurofibroma, management consists of surgical removal. With multiple or massive involvement, surgical removal may be impossible to carry out and is indicated only when malignant changes are suspected. With von Recklinghausen's disease, there is a 5% to 15% risk of malignant degeneration.

Papilloma

A papilloma is a benign epithelial neoplasm composed of fingerlike projections of

squamous epithelium. Some authors use the term squamous papilloma.

The cause is unknown, although a virus is most likely. Oral and oropharyngeal papillomas may occur as single or multiple, sessile, warty lesions, seldom measuring more than a few millimeters. When they involve the oropharynx, the soft palate and the uvula are the usual sites. The clinical differential diagnosis of a papilloma includes verruca vulgaris, fibroepithelial polyp, focal epithelial hyperplasia, and condyloma acuminatum. The histology of a papilloma shows fingerlike projections of squamous epithelium above the level of the surrounding mucosa. In most cases a mild hyperorthokeratosis occurs. Epithelial dysplasia is not a feature of papilloma. Carcinomatous changes in a papilloma are exceptional, if indeed ever proven. Management consists of surgical excision. Recurrences are rare.

Odontogenic Tumors

Odontogenic tumors comprise an unusual group of lesions of the jaws, derived from primordial tooth-forming tissues and presenting in a large number of histologic patterns. Some of these lesions, particularly the odontomas, are now interpreted as developmental malformations or hamartomatous lesions rather than true neoplasms. Other lesions, such as ameloblastoma, are accepted as true neoplasms and must be diagnosed and treated as such. Most odontogenic tumors are essentially benign lesions but infiltrate the adjacent bone between the spicules of the medulla. This form of bony infiltration, common to many benign tumors of bone, is not the true invasiveness of malignant tumors but represents a clinical problem in that the tumor can recur after surgical therapy if the bony margins still contain some of the tumor infiltration.

In general terms, odontogenic tumors tend to be more common in younger patients but can occur at any age They originate in the jaws and usually are found in the tooth-bearing sites. They are often associated with impacted or missing teeth. The common sites for odontogenic tumors are the mandibular molar region and the maxillary cuspid region. Odontogenic tumors are usually slowly growing and asymptomatic. Pain is not a feature of benign tumors of the jaws but is a common symptom of malignant tumors of the jaws. The odontogenic tumors are expansile lesions and may expand the bony cortex, but usually do not invade or perforate it. Radiographically, odontomas will present as mixed radiolucent and radiopaque lesions. Among true neoplasms, the radiographic appearance may vary from entirely radiolucent to the mixed one.

Odontomas usually occur in cyst-like cavities with a connective tissue lining. They can be removed surgically by simple enucleation and will not recur since they are not true neoplasms and do not infiltrate the contiguous bone. Neoplasms such as ameloblastoma are benign tumors and treated by conservative surgical removal. Simple enucleation rarely offers a permanent cure for ameloblastoma since the tumor will eventually recur from the infiltrative foci at the tumor margin. A block resection leaving the cortical lower border of the mandible intact is favored. These benign tumors are relatively unaffected by radiation, and the risk of radiation stimulating the development of a malignant tumor or of radiation necrosis is unwarranted for a benign tumor.

Over the years, very extensive and complicated classifications have been used for the odontogenic tumors and related lesions. A simple classification will suffice, based on the derivation of the lesions and the degree of cellular differentiation involved lesions, which probably are different from odontogenic lesions but which are frequently included in this general topic, are periapical cemental dysplasia and florid cemento-osseous dysplasia, peripheral odontogenic fibroma and odontogenic epithelial hamartoma of gingiva, craniopharyngioma, adamantinoma of long bones, and teratoma.

Odontogenic lesions share two major characteristics (1) they arise from tissue with the potential for differentiation into tooth or periodontal ligament structures, and (2) they are found predominantly to arise at tooth-bearing sites. Variable but distinctive features of odontogenic lesions include (1) formation of tooth-related extracellular substance, some of which may calcify and be visible on radiographs, and (2) epithelial-mesenchymal interactions ("induction").

Odontogenic lesions vary widely in their degree of differentiation, and there is a rough correlation between the degree of differentiation and the biologic behavior associated with any given lesion. True malignant transformation of benign odontogenic lesions or the development of malignancy de novo from odontogenic tissues have both been reported, but such occurrences are extremely rare. In general, the less-differentiated odontogenic lesions (the immature ones) are more likely to have indistinct radiographic borders, invasive growth patterns, and relatively aggressive clinical behavior, while the mature or well-differentiated entities are more likely to produce recognizable extracellular product, to be well circumscribed, and to be self-limiting in terms of growth.

Although odontogenic lesions may be discovered at any age, certain lesions are typically found in patients of particular age groups and certain sites; knowledge of these patterns and careful radiographic interpretation enable the astute clinician to make an accurate clinical diagnosis of odontogenic lesions fairly frequently.

Periapical cyst

A periapical (radicular) cyst is the most common odontogenic cyst. The usual etiology is a tooth that becomes infected, leading to necrosis of the pulp. Toxins exit the apex of the tooth, leading to periapical inflammation. This inflammation stimulates the Malassez epithelial rests, which are found in the periodontal ligament, resulting in the formation of a periapical granuloma that may be infected or sterile. Eventually, this epithelium undergoes necrosis caused by a lack of blood supply, and the granuloma becomes a cyst. The lesions are not usually clinically detectable when small but most often are discovered as incidental findings on radiographic survey.

Radiographically, distinguishing between a granuloma and a cyst is impossible, although some say that if the lesion is quite large it is more likely to be a cyst. They both present as radiolucent lesions in association with the apex of a nonvital tooth. Occasionally, these lesions can become quite large because they grow in response to pressure. However, granulomas and cysts are not neoplastic.

Microscopically, the epithelium is a nondescript stratified squamous epithelium without keratin formation. Inflammatory changes may be observed in the cyst wall, and these changes, in turn, may lead to epithelial changes (eg, ulceration, atrophy, hyperplasia). In particularly inflamed lesions, cholesterol slits and/or foamy macrophages may be apparent.

Several treatment options exist for such cysts. Many cysts resolve with endodontic therapy of the involved tooth. Those lesions should be monitored radiographically to ensure such resolution. Lesions that fail to resolve with such therapy should be surgically removed and histopathologically examined. Although these cysts arise from a mature resting epithelium and thus have a relatively low growth potential, a squamous cell carcinoma occasionally may arise de novo in a radicular cyst, thus the recommendation for histopathologic examination of all tissues removed.

Dentigerous cyst

The second most common odontogenic cyst is the dentigerous cyst, which develops within the normal dental follicle that surrounds an unerupted tooth. The dentigerous cyst is not thought to be neoplastic. It most frequently is found in areas where unerupted teeth are found: mandibular third molars, maxillary third molars, and maxillary canines, in decreasing order of frequency. These cysts can grow very large and can move teeth, but, more commonly, they are relatively small. Most dentigerous cysts are asymptomatic, and their discovery is usually an incidental finding on radiography.

The usual radiographic appearance is that of a well-demarcated radiolucent lesion attached at an acute angle to the cervical area of an unerupted tooth. The border of the lesion may be radiopaque. The radiographic differentiation between a dentigerous cyst and a normal dental follicle is based merely on size.

However, histologically, a distinction other than size is found. The dental follicle normally is lined by the reduced enamel epithelium while the dentigerous cyst is lined with a stratified squamous nonkeratinizing epithelium. Dystrophic calcification and clusters of mucous cells may be found within the cysts.

Dentigerous cysts develop from follicular epithelium, and follicular epithelium has greater potential for growth, differentiation, and degeneration than the epithelium from which radicular cysts arise. Occasionally, other more ominous lesions arise within the walls of the dentigerous cyst, including mucoepidermoid carcinoma arising from mucous cells within the cyst walls, ameloblastoma, and squamous cell carcinoma. As previously mentioned, dentigerous cysts also can become quite large and can place the patient at risk for pathologic jaw fracture.

These findings comprise most of the medical rationale for removal of impacted third molars with pericoronal radiolucencies; however, impacted teeth with small pericoronal radiolucencies (suggesting the presence of normal dental follicle rather than dentigerous cyst) also may be monitored with serial radiographic examination. Any increase in the size of the lesion should prompt removal and histopathologic examination. Any lesion that appears larger than a normal dental follicle indicates removal and histopathologic examination.

Ameloblastoma

Ameloblastoma is an entirely epithelial tumor arising from the dental lamina, Hertwig sheath, the enamel organ, or the lining of dental follicles/dentigerous cysts. Ameloblastoma is the most common epithelial odontogenic tumor. Ameloblastomas usually occur in individuals aged 20-40 years; however, the unicystic variant most often occurs in adolescents. This lesion occurs in both the maxilla and mandible, but the posterior mandible is the most common location; only 20% of lesions are found in the maxilla. The lesion is distributed equally between males and females.

Although ameloblastoma generally is not classified as a malignant lesion (a rare malignant variant exists), it is extremely aggressive and infiltrative. Many have suggested that this lesion should be considered a low-grade or indolent malignancy, similar to basal cell carcinoma. Many histologic and behavioral similarities are found between the 2 lesions. It generally does not metastasize but is slow growing, persistent, and hard to eradicate. If ameloblastoma is not noticed as an incidental finding on radiographs taken for other purposes, the first symptom is usually painless bony expansion. Ameloblastomas typically appear as an expansile multilocular radiolucency in the area of the lower third molar, but they may be found anywhere in the jaws. These lesions may be unilocular when small, and they often resorb the teeth they contact. These lesions are never radiopaque. The treatment of ameloblastoma is surgical excision with wide free margins. Appropriate reconstruction may be performed at the same time. All patients with ameloblastoma, regardless of surgical treatment method or histologic type, must be monitored radiographically throughout their lifetime. If excision is inadequate, recurrence is common.

Complex odontoma

Complex odontoma lesions represent further histologic differentiation of the odontogenic pluripotential epithelium. Findings from this lesion resemble those of ameloblastic fibro-odontoma but extended one step further. The epithelium in this lesion has involuted, leaving disorganized dental hard tissues in place. These are common lesions, and they persist throughout life. They usually are detected in adolescence and have a predilection for the mandibular molar regions; however, they can be found in other areas of the jaws. These lesions generally are described as sunburst radiopacities surrounded by a thin, uniform, radiolucent rim. Although this description may have some superficial resemblance to the radiographic description of osteosarcoma, the association with a tooth, the clear demarcation of the lesions' borders, and the lack of pain and/or swelling serve to delineate this very benign lesion from osteosarcoma. Simple removal or radiographic observation is the method of treatment. These lesions do not recur.

Compound odontoma

This is the most common odontogenic tumor. It represents the product of both histodifferentiation and morphodifferentiation of odontogenic tissues, resulting in what appears as a cluster of multiple abortive teeth. It most commonly is found in the maxillary anterior alveolar bone but may be located anywhere within the tooth-bearing segments of the jaws. It is often responsible for preventing normal tooth eruption, thus it usually is discovered during adolescence. Multiple tiny toothlike structures are contained within a fine radiolucent rim. Simple removal is the method of treatment. These lesions do not recur.

Cementoblastoma

Cementoblastoma, as distinguished from cementoma, is a true neoplasm of cementum. This benign neoplasm is rare and usually is observed in patients younger than 25 years. It most often is found in association with the apex of the mandibular first molars (50% of lesions), and it is never found in association with the anterior dentition. The lesion is usually asymptomatic, though occasionally the associated tooth may be slightly sensitive to percussion. A round opaque sunburst mass attached to the apex of a tooth that is well-demarcated and surrounded by a thin radiolucent rim is observed. The lesion obscures the lamina dura. Students sometimes confuse it with condensing osteitis, a common lesion resulting from low-grade periapical irritation that stimulates bone growth. Although the most usual location for the 2 lesions is the same, condensing osteitis does not obscure the periodontal ligament (PDL) space and tends to be more irregular in outline. The mature cementoma, also known as periapical cemental dysplasia, is another common lesion that students may confuse with cementoblastoma. However, cementoma usually is located in the mandibular anterior region and does not obscure the PDL space. Cementomas actually have 3 developmental stages: osteolytic (at which point the lesion appears as a radiolucency), cementoblastic (mixed radiolucent/radiopaque), and mature (radiopaque). Removal of attached tooth and tumor is the method of treatment. No recurrences are reported.

Salivary tumors

Tumors of the salivary gland are rather uncommon and represent 2-3% of head and neck neoplasms. The glands are divided into major and minor salivary gland categories. The major glands are parotid, submandibular, and sublingual. The minor glands are dispersed throughout the upper aerodigestive submucosa (ie, palate, lip, pharynx, nasopharynx, larynx, parapharyngeal space). The ubiquitous deposition of the minor salivary glands makes the diagnosis and management of salivary gland tumors (SGTs) rather challenging. The appropriate approach for management begins with an accurate histopathologic diagnosis. The larger glands have the highest incidence of tumors and the highest percentage of benign tumors. Pleomorphic adenoma (benign mixed tumor) is the most common benign SGT, comprising 85% of all salivary gland neoplasms. SGTs usually manifest as an enlargement of the salivary glands. Investigate weight loss, underlying infectious processes (eg, chest pain, cough, lymphadenopathy), and clinical indications of lymphoma-type B symptoms (eg, night sweats, fever). Tumors of the salivary glands are grouped into epithelial, nonepithelial, and metastatic categories. Benign epithelial tumors include pleomorphic adenoma (80%), Warthin tumor, (3) monomorphic adenoma, intraductal papilloma, oncocytoma, and sebaceous neoplasms.

Benign nonepithelial tumors (mesenchymal origin) include lipoma, hemangioma, angioma, lymphangioma (cystic hygroma), and neural sheath tumors.

Pleomorphic adenoma

This type of tumor is commonly located at the tail of the parotid. For the minor glands, the hard palate is the site most frequently involved.

Pleomorphic adenoma consists of epithelial and connective tissue components in varying degrees. It is round, smooth, and freely mobile. This tumor grows slowly, although it may achieve a size larger than other salivary gland tumors. It is characterized by a thin, delicate capsule with occasional projections into the surrounding parotid tissue. This is of particular clinical significance because obtaining clean margins and avoiding spillage are mandatory to minimize recurrence.

Microscopically, benign mixed tumors are characterized by variable, diverse, structural histologic patterns. Frequently, they have growth patterns of sheets, strands, or islands of spindle and stellate cells, with a myoid configuration occasionally predominating. Treatment of benign neoplasms is complete surgical excision of the affected gland. If the parotid is the gland involved, superficial parotidectomy with standard facial nerve dissection and preservation is the procedure of choice. Avoid tumor spillage of a pleomorphic adenoma because it can lead to tumor recurrence.

Tumors of the parotid gland are the most common and are 5 times more common than tumors of the minor salivary glands. The latter are almost twice as common as neoplasms occurring in the submandibular gland. The incidence of salivary gland neoplasms peaks in the fifth decade of life. The most common benign tumor is the benign mixed tumor, or pleomorphic adenoma.

Most minor SGTs are malignant. Overall, adenoid cystic carcinoma is the most common malignant tumor of all minor salivary glands. The submandibular gland has a high incidence of malignant tumors (65% malignant vs 35% benign).

An associated long-standing history of smoking and a strong family history may be risk factors. SGTs are indolent, painless, and well-circumscribed tumors. A new onset of symptoms may indicate the presence of malignancy. Rapid growth of the mass also may raise the consideration of a malignant etiology.

SGTs have a wide spectrum of histopathological forms, due to the diversity of cell types harbored in the glands. Saliva production is the product of the acinar cells, ductal cells, and myoepithelial cells. Any of these cells may produce either benign or malignant tumors.

SGTs manifest as a painless mass on the face (parotid), the angle of the jaw (parotid tail, submandibular), the neck (submandibular), or as a swelling at the floor of the mouth (sublingual). Sometimes, bleeding and airway compromise are the first signs of minor SGTs of the nasal septum. The authors have observed one patient treated for a pleomorphic adenoma of the nasal septum.

A new onset of pain, facial nerve weakness, paresthesias, and hoarseness of the voice are indicators of possible underlying malignancy. Trismus usually represents invasion to the masseter or pterygoid muscles. Skin involvement and fixation to the mastoid tip are also signs of malignancy.

As a general rule, all SGTs should be excised. Eneroth et al and others have advocated fine-needle aspiration (FNA) application and reported accuracy rates of 74-90%. FNA is mainly useful in nonneoplastic masses, metastatic tumors to the parotid gland, and nonsurgical lymphomas.

Almost all neoplasms should be removed surgically because only positive diagnostic results from FNA are significant.

Surgical removal is always the management choice, with attention to preservation of the facial nerve in benign tumors and of the parotid gland in malignant tumors, when no evidence of neural invasion is observed. When direct invasion is present, sacrificing the nerve and immediate nerve grafting is commonplace.

Surgical removal of the submandibular gland exposes the lingual and the hypoglossal nerves to potential injury. The mandibular branch of the facial nerve also could be in jeopardy because of anatomical proximity.

Malignant tumors of the jaws

Definition

Malignant tumors represent an uncontrolled growth of tissue. Unlike benign neoplasms, they are more locally invasive, have a greater degree of anaptasia. and have the ability to metastasize regionally to lymph nodes or distantly to other sites. Cancers may be caused by viruses, significant radiation exposure, genetic defects, and exposure to carcinogenic chemicals. For instance, using tobacco is strongly associated with oral carcinoma. Malignant tumors that arise de novo are termed primary tumors, and those that originate from distatit primary tumors are termed secondary or methastatic

The most convenient method of classification of cancers is based on histopathoiogy. In the following text the malignancies that commonly affect the jaws have been divided into one of four categories: carcinomas (lesions of epithelial origin), mctastatic lesions from distant sites, sarcomas (lesions of mesenchymal origin), and malignancies of the heoiatopoietic system. Unusual malignant tumors have been omitted to concentrate on more common lesions that a general practitioner may encounter.

Clinical Features

The following are clinical signs and symptoms that suggest that a lesion may be malignant: swelling, displaced teeth, loosened teeth over a short duration, foul smell, ulceration. presence of an indurated or rolled border, exposure of underlying bone, sensory or motor neural deficits, lymphadenopathy, weight loss, dysgeusia, dys-phagia, dysphonia, hemorrhage, lack of normal healing, or pain with no demonstrable dental cause. Most oral cancers occur in men aged 50 years and older; however, malignant tumors may occur at any age in either gender. Dentists must vigilantly watch for the possibility of malignancy in their patients. Because the prevalence of oral malignancy is low, many general practitioners practice for years without encountering a patient who has a malignant tumor. This rarity may make a dentist less likely to recognize a malignant condition when it does exist. The risks of lack of attention to this possibility arc delayed diagnosis, delayed treatment, increased need for aggressive treatment with added morbidity, and, in the worst case, premature death.

Radiographic Examination

Radiology has a number of important roles in the management of the patient with cancer. First, diagnostic images may aid in the establishment of an initial diagnosis of a tumor. Diagnostic imaging also aids in the appropriate staging of disease from early small cancers to large cancers that have spread. Appropriate radiologic investigations assist the surgeon or radiation oncologist to determine the appropriate dimensions of the tumor so that it can be excised or irradiated adequately. Radiologic investigation has the potential to determine the presence of osseous involvement from soft tissue tumors and allow the practitioner to assess the presence of nodal disease and the outcome of treatment. Finally, a thorough radiographic dental examination plays a part in the management of the cancer survivor, who often is rendered xerostomic and susceptible to both dental caries and periodontal disease.

RADIOGRAPHIC FEATURES

The following features may suggest the presence of a malignant tumor. The absence of visible radiologic signs as described does not preclude malignancy. It only implies that no visible radiographic signs exist.

Location

Primary and metastatic malignant tumors may occur anywhere in the oral and maxillofacial region. Primary carcinomas are more commonly seen in the tongue, floor of the mouth, tonsillar area, lip, soft palate, or gin-giva and may invade the jaws from any of these sites. Sarcomas are more common in the mandible and in posterior regions of both jaws. Metastatic tumors are most common in the posterior mandible and maxilla.

Periphery and Shape

The typical appearance of the periphery of a malignant lesion is an ill-defined border with lack of cortication and absence of encapsulation (a soft tissue or radiolucent periphery). This infiltrative border has uneven extensions of bone destruction. Fingerlike extension of the tumor occurs in many directions; this extension is followed by osseous destruction producing a region of radiolucency. Evidence of osseous destruction with adjacent soft tissue mass is highly suggestive of malignancy. Such a mass may exhibit a smooth or ulcerated peripheral border if cast against a radiolucent background. The shape of a malignant tumor of the jaw is irregular.

Because most malignancies do not produce bone nor do they stimulate the formation of reactive bone, the internal aspect is typically radiolucent in most instances. Occasionally residual islands of bone are present, resulting in a pattern of patchy destruction with some scattered residual internal osseous structure. Some tumors, such as prostate and breast metastatic lesions, can induce bone formation, resulting in an abnormal-appearing internal osseous architecture, whereas others, such as osteogenic sarcomas, can be productive in nature, causing frank sclerosis.

Effects on Surrounding Structures

Malignancy is destructive, often rapidly so. The effect on surrounding structures mirrors this behavior. Slower-growing benign tumors or cysts may resorb or displace teeth in a bodily fashion without causing loose teeth. In contrast, rapidly growing malignant lesions generally destroy supporting alveolar bone so that teeth may appear to be floating in space.

Occasionally root resorption is present, this being more common in sarcomas. Internal trabecular bone is destroyed, as are cortical boundaries such as the sinus floor, inferior border of the mandible, follieular cortices, and the cortex of the inferior alveolar ncurovascular canal. Because malignant tumors tend to grow rapidly, they invade by means of the easiest routes such as through the maxillary antrum or through the periodontal ligament space around teeth, resulting in, irregular widening with destruction of the lamina dura. Where the tumor has destroyed the outer cortex of bone, usually no periosteal reaction occurs; however, some tumors stimulate unusual periosteal new bone formation. Lesions such as osteosarcoma and prostate metastatic lesions as well as other tumors can stimulate the formation of thin straight spicules of bone, giving a hair-on-end or sunburst appearance.

Carcinomas

SQUAMOUS CELL CARCINOMA ARISING IN SOFT TISSUE

Definition. Squamous cell carcinoma, the most common oral malignancy, may be defined as a malignant tumor originating within the surface epithelium. It is characterized initially by invasion of malignant epithelial cells into the underlying connective tissue with subsequent spread into deeper soft tissues and occasionally into adjacent bone, local-regional lymph nodes, and ultimately to distant sites such as the lung, liver, and skeleton.

Clinical features. Squamous cell carcinoma appears initially as white or red (sometimes mixed) irregular patchy lesions of the affected epithelium. With time these lesions exhibit central ulceration; a rolled or indurated border, which represents invasion of malignant cells; and palpable infiltration into adjacent muscle or bone. Pain may be variable, and regional lymphadenopathy with hard lymph nodes that may or may not be tethered to underlying structures may be present. Other clinical features include a soft tissue mass, paresthesia, anesthesia, dyscsthesia, pain, foul smell, trismus, grossly loosened teeth, or hemorrhage. Large lesions can obstruct the airway, the opening of the eustachian tube (leading to diminished hearing), or the nasopharynx. Patients often report a significant weight loss and feel unwell. Males are more commonly affected than females. The condition is often fatal, if untreated. Most squarnous cell carcinomas occur in persons older than 50 years.

Radiographic features

Location. Squamous cell carcinoma commonly involves the lateral border of the tongue. Therefore a common site to observe bone invasion is the posterior mandible. Lesions of the lip and floor of the mouth may invade the anterior mandible. Lesions involving attached gingiva and underlying alveolar bone may mimic inflammatory disease such as periodontal disease.

Periphery and Shape. Squamous cell carcinoma may erode into underlying bone from any direction, producing a radiolucency that is polymorphous and irregular in outline. Invasion occurs in one half of cases and is characterized most commonly by non-corticated border. Rarely the bolder may appear smooth, indicating underlying erosion rather than invasion. If bone involvement is extensive, the periphery appears to have fingerlike extensions preceding a zone of impressive osseous destruction. If pathologic fracture occurs, the borders show sharpened thinned bone ends with displacement of segments and an adjacent soft tissue mass. Surface carcinomas are capable of producing sclerosis in underlying osseous structures without frank invasion.

Internal Structure. The internal structure of squamous cell carcinoma in jaw lesions is totally radiolucent; the original osseous structure can be completely lost. Occasionally small islands of residual normal trabecular bone are visible within this central radiolucency.

Differential diagnosis. Squamous cell carcinoma is discernible from other malignancies by its clinical and histologic features. Occasionally it is difficult to differentiate inflammatory lesions such as osteomyelitis from squamous cell carcinoma, especially when oral bacteria secondarily infect the tumor. Both osteomyelitis and squamous cell carcinoma are destructive, leaving islands of osseous structure that may appear to be consistent with sequestra. Evidence of profound bone destruction or invasive characteristics helps to identify the presence of a malignancy when a mixture of inflammatory changes and carcinoma exists. Osteomyelitis usually produces some periosteal reaction, whereas squamous cell carcinoma does not. In cases of osteoradionecrosis, the differentiation of this condition from squamous cell carcinoma requires advanced imaging or surgical exploration.

Management. Oral squamous cell carcinoma is usually managed using a combination of surgery and radiation therapy. The choice of which modality to use depends on the protocol of the treating center and the location and severity of the tumor. Generally, if an adequate margin of normal tissue can be obtained, surgery is the usual treatment, followed by radiation treatment. Alternately, radiation may be used as the primary treatment followed by surgical salvage. Currently, the trend is to add concomitant chemotherapy as an adjunct to either radiation or surgical treatment.

SQUAMOUS CELL CARCINOMA ORIGINATING IN BONE

Definition. Primary intraosseous carcinoma is a squamous cell carcinoma arising within the jaw that has no original connection with the surface epithelium of the oral mucosa. Primary intraosseous carcinomas are presumed to arise from intraosseous remnants of odontogenic epithelium. In addition, carcinoma from surface epithelium, odontogenic cysts, or distant sites (metastases) must be excluded.

Clinical features. These neoplasms are rare and may remain silent until they have reached a fairly large size. Pain, pathologic fracture, and sensory nerve abnormalities such as lip paresthesia and lymphadenopathy may occur with this tumor. It is more common in men and in patients in their fourth to eighth decade of life. The surface epithelium is invariably normal in appearance.

Radiographic features

Location. The mandible is far more commonly involved than the maxilla, with most cases being present in the molar region and less frequently in the anterior aspect of the jaws. Because the lesion is by definition associated with remnants of the dental lamina, it originates only in tooth-bearing parts of the jaw.

Periphery and shape. The periphery of the majority of lesions is ill-defined, although some have been described as well-defined. They are most often rounded or irregular in shape and have a border that demonstrates osseous destruction and varying degrees of extension at the periphery. The degree of raggedness of the border may reflect the aggressiveness of the lesion. If sufficient in size, pathologic fracture occurs, with its associated step defects, thinned cortical borders, and subsequent soft tissue mass. The internal structure is wholly radiolucent with no evidence of bone production and very little residual bone left within the center of the lesion. If the lesion is small, overlying buccal or lingual plates may cast a shadow that may mimic the appearance of internal trabecular bone.

Effects on surrounding structures. These lesions are capable of causing destruction of the antral or nasal floors, loss of the cortical outline of the mandibular neurovascular canal, and effacement of the lamina dura. Root resorption is unusual. Teeth that lose both lamina dura and supporting bone appear to be floating in space.

Differential diagnosis. If the lesions are not aggressive and have a smooth border and radiolucent area, they may be mistaken for pcriapical cysts or granulomas. Alternately, if lesions are not centered about the apex of a tooth, occasionally it is difficult to differentiate this condition from odontogenic cysts or tumors. If the border is obviously infiltrative with extensive bone destruction, a metastatic lesion must be excluded, as well as multiple myeloma, fibrosarcoma, and carcinoma arising in a dental cyst. Examination of the oral cavity and especially the surface epithelium assists in differentiating this condition from surface squamous cell carcinoma.

Management. Generally these tumors are excised with their surrounding osseous structure in an en bloc resection. Radiation and chemotherapy may be used as adjunctive therapies.

Met astatic Tumors

Definition. Mctastatic tumors represent the establishment of new foci of malignant disease from a distant malignant tumor. An interesting feature of these lesions is that metastatic lesions in the jaws usually arise from sites that arc anatomically inferior to the clavicle. Metastatic lesions of the jaws usually occur when the distant primary lesion is already known, although on occasion a jaw metastatic tumor may reveal the presence of a silent primary lesion. Jaw involvement accounts for less than 1 % of metastatic malignancies found elsewhere, with most affecting the spine, pelvis, skull, ribs, and humerus. Most frequently the tumor is a type of carcinoma, the most common primary sites being the breast, kidney, lung, colon and rectum, prostate, thyroid, stomach, melanoma, testes, bladder, ovary, and cervix. In children the tumors include neuroblastorna, retinoblastoma, and Wilms' tumor. Metastatic carcinoma must be differentiated from the more common locally invading squamous carcinoma.

Clinical features. Metastatic disease is more common in patients in their fifth to seventh decade of life. Patients may complain of dental pain, numbness or pares-thesia of the third branch of the trigeminal nerve, pathologic fracture of the jaw, or hemorrhage from the tumor site.

Radiographic features

Location. The posterior areas of the jaws are more commonly affected, the mandible being favored over the maxilla. The maxillary sinus may be the next most common site, followed by the anterior hard palate and mandibular condyle. Frequently metastalic lesions of the mandible are bilateral. Also, lesions may be located in the periodontal ligament space (sometimes at the root apex), mimicking periapical inflammatory disease, or in the papilla of a developing tooth.

Periphery and shape. Metastatic lesions may be moderately well demarcated but have no cortication or encapsulation at their tumor margins; they may also have ill-defined invasive margins. The lesions are not round but polymorphous in shape. Both prostate and breast lesions may stimulate bone formation of the adjacent bone, which will be sclerotic. The tumor may begin as a few zones of osseous destruction separated by normal bone. After a time these small areas coalesce into a larger, ill-defined mass and the jaw may become enlarged. Lesions are generally radiolucent, in which case the internal structure is a combination of residual normal trabecular bone in association with areas of bone lysis. If sclerotic metastases are present (i.e., prostate and breast), the normally ragged radiolucent area may appear as an area of patchy sclerosis, the result of new bone formation. The origin of this new bone is not the tumor but stimulation of surrounding normal bone. If the tumor is seeded in multiple regions of the jaw, the result is a multifoeal appearance (multiple small radiolucent lesions).

Differential diagnosis. In most cases a known primary malignancy is present, and the diagnosis of metastasis is straightforward. Multiple myeloma may be confused with metastatic tumors; however, the border of multiple myeloma is usually better circumscribed than in metastatic disease. When a lesion starts within the periodontal ligament space of a tooth, the appearance may be identical to that of a periapical inflammatory lesion. A point of differentiation is that the periodontal ligament space widening from inflammation is at its greatest width and centered about the apex of the root. In contrast, the malignant tumor usually causes irregular widening, which may extend up the side of the root. Odontogenic cysts, if secondarily infected, may have an ill-defined border giving a similar appearance to a metastatic lesion. Invasion of the jaws by primary tumors of the overlying epithelium such as squamous cell carcinoma may be indistinguishable from metastatic disease but can be differentiated by clinical examination.

Management. The presence of a metastatic tumor in the jaw indicates a poor prognosis. If metastatic disease is present, the patient will usually die within 1 to 2 years. If the radiographic appearance is suspicious, an opinion from a dental radiologist should be sought and tissue submitted for histologic analysis. Nuclear medicine may be employed to detect other metastatic lesions. Isolated malignant deposits, if symptomatic, may be treated with localized high-dose radiation treatment. In the rare occasion that the jaw is the first diagnosed site of malignant spread, it is imperative that the patient be referred quickly to an oncologist so that anticancer treatment can be delivered promptly. This treatment may take the form of chemotherapy, radiation therapy, surgery, immunotherapy, and hormone treatment.

OSTEOSARCOMA

Definition. Osteosarcoma is a malignant neoplasm of bone in which osteoid is produced directly by malignant stroma as opposed to adjacent reactive bone formation. The three major histologic types are chondroblastic, osteoblastic, and fibroblastic osteosarcoma. The cause of osteosarcoma is unknown, but genetic mutation and viral causes have been suggested. It is also known to occur in association with Paget's disease and fibrous dysplasia after therapeutic irradiation.

Clinical features. Osteosarcoma of the jaws is quite rare and accounts for approximately 7% of all osteosarcomas. Despite its rarity, the dentist may be the first health professional who observes tumors involving the jaws. The lesion occurs in all racial groups worldwide and in males twice as frequently as females. Jaw lesions typically occur with a peak in the fourth decade, about 10 years later on average than long bone lesions. The most commonly reported symptom or sign is swelling, which may be present as long as 6 months before diagnosis; the swelling is usually rapid. Other indicators are pain, tenderness, erythema of overlying mucosa, ulceration, loose teeth, epistaxis, hemorrhage, nasal obstruction, exophthalmos, trismus, and blindness. Hypoesthesia has also been reported in cases involving neurovascular canals.

Radiographic features

Location. The mandible is more commonly affected than the maxilla. Although the lesion can occur in any part of either jaw, the posterior mandible, including the tooth-bearing region, angle, and vertical ramus, is most commonly affected.

Periphery and shape. Osteosarcoma has an ill-defined border in most instances. When viewed against normal bone, the lesion is usually radiolucent with no peripheral sclerosis or encapsulation. If the lesion involves the periosteum directly or by extension, one may see the typical sunray spicules or "hair-on-end" trabeculae. This occurs when the periosteum is displaced,

Osteosarcoma maybe entirely radiolucent, mixed radioluccnt-radiopaque, or quite radiopaque. The internal osseous structure may take the appearance of granular- or sclerotic-appearing bone, cotton balls, wisps, or honeycombed internal structures in areas with adjacent destruction of the preexisting osseous architecture. Whatever the resultant internal structure, the normal trabecular structure of the jaws is lost.

Effects on surrounding structures, widening of the periodontal membrane suggests osteosarcoma but is also seen in other malignancies. The antral or nasal wall cortices may be lost in maxillary lesions. Mandibular lesions may destroy the cortex of the neurovascular canal and adjacent lamina dura. Alternatively, the ncurovascular canal may be symmetrically widened and enlarged. Effects on the periosteum are discussed under the discussion on periphery.

Differential diagnosis. If internal structure is minimal or absent, fibrosarcoma or metastatic carcinoma may appear similar to osteosarcoma. If osseous structure is

visible, the practitioner should also consider chondrosarcoma. If spiculated periosteal new bone is present, prostate and breast metastases should be considered. Comprehensive physical examination and laboratory tests assist in determining if the lesion is primary or metastatic. Benign tumors such as ossifying fibroma and benign conditions such as fibrous dysplasia may mimic osteosarcoma. The former conditions, however, are usually better demarcated and have a more uniform internal structine. The histopathology of osteosarcoma may be interpreted as a benign fibroosseous lesion, and in these cases, the correct diagnosis may rely on the radiographic characteristics alone. Ewing's sarcoma, solitary plasmacytoma, and even osteomyelitis share some of the radiographic characteristics of osteosarcoma. Osteosarcoma is generally not associated with signs of infection.

Management. The management of osteosarcoma is resection with a large border of adjacent normal bone. This may be possible in orthopedic cases but may be complicated by the presence of important adjacent anatomic structures in the head and neck. Generally radiation therapy and chemotherapy are used only for controlling metastatic spread or for palliation.

Malignancies of the Hematopoietic System

MULTIPLE MYELOMA

Definition. Multiple myeloma is a malignant neoplasm of plasma cells. It is the most common malignancy of bone in adults. Single lesions are called plasmacytoma, and multiple lesions arc termed multiple myeloma.

Clinical features. Multiple myeloma is a fatal systemic malignancy. A patient with multiple myeloma is usually lacks any sign of bone reaction. The lesions have been described as appearing "punched out." However, many appear ragged and even infiltrative. Some lesions have an oval or cystic shape. Untreated or aggressive areas of destruction may become confluent, giving the appearance of multilocularity. If the lesion is located in the periapical periodontal ligament space, it may have a border similar to that seen in inflammatory or infectious periapical disease. Soft tissue lesions have been reported in the jaws and nasopharynx. When visible on radiographs, they appear as smooth-bordered soft tissue masses, possibly with underlying bone destruction.

Internal structure. No internal structure is radio-graphically visible. Occasionally islands of residual bone, yet unaffected by tumor, give the appearance of the presence of new trabecular bone within the mass. Very rarely the lesions appear radiopaque internally.

Differential diagnosis. The most likely disease to be mistaken for multiple myeloma is the radiolucent form of metastatic carcinoma. Knowledge of a prior malignancy in a patient may help differentiate multiple myeloma from metastatic carcinoma. Osteomyelitis, if severe, may yield a radiologic picture similar to that of multiple myeloma; however, a visible cause for it usually exists. In addition, inflammatory lesions and infections in general cause sclerosis in adjacent bone, which multiple myeloma does not. Simple bone cysts may be bilateral in the mandible and therefore may be mistaken for multiple myeloma. They are usually corticated in part and characteristically interdigi-tate between the roots of the teeth in a much younger population. Generalized radiolucency of the jaws may be caused by hyperparathyroidism but is differentiated based on abnormal blood chemistry.

Management. The management of multiple myeloma is usually chemotherapeutic with or without autologous or allogeneic bone marrow transplantation. Radiation therapy may be used for treatment of symptomatic osseous lesions when palliation is required.

LEUKEMIA

Definition. Leukemia is a malignant tumor ofhema-topoietic stem cells. These malignant cells displace normal bone marrow constituents and spill out into the peripheral blood. They are subdivided into acute leukemias and chronic leukemias and further subdivided by the cell of origin. The acute leukemias occur with a bimodal age distribution, with very young patients and very old patients being the most commonly affected. Most leukemias are associated with nonrandom chromosomal abnormalities.

Clinical features. The patient with chronic leukemia may have no presenting signs or complaints. Acute leukemia patients generally feel unwell with weakness and bone pain. They may exhibit pallor, spontaneous hemorrhage, hepatomegaly, splenomegaly, lymphadenopathy, and fever. Oral symptoms are generally absent but if present include loose teeth, petechiae, ulceration, and boggy enlarged gingiva.

Radiographic features. Radiologic signs associated with the chronic leukemias are comparatively rare.

Differential diagnosis. Generally, by the time oral radiologic signs of leukemia are present, a medical diagnosis has been reached. However, the development of radiologic changes may be the first indication of the relapse of treatment. Occasionally lymphoma or neuroblastoma may mimic some of the features of destruction seen in leukemia. Metabolic disorder may be considered in those cases in which generalized rarefaction of bone is seen. These conditions are all excluded based on blood testing. With apical lesions, careful examination of the involved tooth clinically and radiologically typically shows no apparent cause for rarefying osteitis.

Management. The management of leukemia is primarily through a combination of chemotherapy with or without allogeneic or autologous bone marrow transplantation. Some chronic leukemias are managed with low-dose chemotherapy.

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|Antrotomy by Denker for management of maxillary tumors |

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|Transfacisal approach to parapharingeal tumors |

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|Approach used for cranio-facial tumors after V. Malanchuk |

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|Neck dissection after Krayl |

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|Facial incisions, used for maxillary resection |

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|Mandibular resection after N.A Plotnikov |

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|Different types of the mandibular resections |

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|Facial incisions used for small soft tissue tumors |

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|Incisions used for benign neck tumors |

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observed by prof. Bernadskyi, 1965

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