13: Tumors of Orofacial Region

Tumors of Orofacial Region

•. Benign Odontogenic Tumors

•. Benign Non-odontogenic Tumors

Squamous Papilloma

Verruca Vulgaris (Oral Warts)

Verrucous Hyperplasia

Condyloma Acuminatum

Focal Epithelial Hyperplasia/Heck’s Disease

Keratoacanthoma/Self-healing Carcinoma

Oral Melanoacanthoma

Acquired Melanocytic Nevus

Ossifying Fibroma

Juvenile Ossifying Fibroma

Peripheral Ossifying Fibroma



Benign Chondroblastoma (Codman’s Tumor)

Benign Osteoblastoma

Giant Cell Granuloma

Peripheral Giant Cell Granuloma

Pyogenic Granuloma

Fibrous Hyperplasia: Denture-related

Congenital Epulis of Newborn


Neurogenic Tumors

Schwannoma (Neurilemmoma)


Traumatic Neuroma



Hemangiomas and Vascular Malformations


Vascular Malformations

Capillary Malformations

Arteriovenous Malformations

Lymphatic Malformations


Giant Cell Fibroma



•. Malignant Odontogenic Tumors

•. Odontogenic Carcinomas

•. Odontogenic Sarcomas

•. Epithelial Malignant Tumors

•. Connective Tissue Malignant Tumors

•. Lymphoid Origin and Hematological Malignancies

Odontogenic Tumors

Odontogenic tumors are lesions of great interest and importance to oral physicians, pathologists and maxillofacial surgeons alike, who for several decades have studied and catalogued these lesions and developed modalities for adequate treatment.

It is estimated that approximately 9% of tumors in the oral cavity are odontogenic in nature, out of which 94.8% are benign and 5.2% are malignant, 58.5% of benign odontogenic tumors are ameloblastoma.

The age predilection for benign odontogenic tumors is around 28 years and for the malignant odontogenic tumors is more than 40 years. Most of the tumors have mandibular predilection with the ratio of 3.2:1, with the maximum in case of ameloblastoma showing a rate of 12.8:1.

There are different ways of defining the content of the term ‘tumor’ in its broadest sense and not restricted to lesions that are definitively neoplastic. Benign tumor is defined as a growth made up of normal cells that have no signs of cancer.

These tumors have some characteristic properties such as new uncoordinated growth that spreads by direct extension unlimited growth potential, do not metastasize, are encapsulated and resemble tissue of origin histologically.

Benign Odontogenic Tumors

These are defined as lesions derived from epithelial or mesenchymal elements or both that are part of tooth forming apparatus. These comprise a group of lesions which have in common the fact that they arise from the odontogenic tissue. These develop from the epithelial part of the tooth germ, the ectomesenchymal part, or from both. Their behavior varies from frankly neoplastic, including meta-static potential, to non-neoplastic hamartomatous. The pathogenesis of these tumors are not clear but can be attributed to the following etiologies.

Theories of Tumor Development

These tumors have been postulated to arise from enamel organ, remnants, epithelium of odontogenic cysts and oral mucosal buddings.


With the first edition of the WHO classification on tumors, about 30 years ago, the terminology and the diagnostic framework became available, and this modern and logically constructed classification greatly intensified research into the subject, and markedly stimulated the urge to publish new findings. In 2000, the International Agency for Research on Cancer (IARC) in Lyon, France started a new book series, WHO Classification of Tumors. The new WHO Blue Books encompass both histopathological and genetic criteria for tumor classification (Table 1). Clinically it also can be classified based on site, age and gender predilection as given in Tables 24.

Table 2

Tumors based on the age of predilection

0–25 years More than 40 years
Adenomatoid odontogenic tumor Calcifying epithelial odontogenic tumor
Ameloblastic fibroma  
Ameloblastic fibro-odontoma Ameloblastoma
Odontoma Squamous odontogenic tumor
Peripheral ossifying fibroma Odontogenic myxoma
Benign cementoblastoma Calcifying odontogenic fibroma
Ameloblastic odontoma  

Table 4

Tumors based on the site of predilection

Maxilla Mandible
Adenomatoid odontogenic tumor Ameloblastoma
Calcifying epithelial odontogenic tumor Ameloblastic odontoma
Ameloblastic fibro-odontoma Benign cementoblastoma
Squamous odontogenic tumor Odontogenic myxoma
  Calcifying odontogenic fibroma

The common clinical features of benign tumors include: slow growing and well-circumscribed swelling, bony expansion, displacement and abnormal mobility of teeth and absence of lymphadenopathy.


Churchill in 1934, defined ameloblastoma as unicentric, non-functional, intermittent growing anatomically benign but clinically persistent. These are benign, locally aggressive polymorphic neoplasms that consist of proliferating odontogenic epithelium.


Leon Barnes has classified ameloblastoma into four types on the basis of behavioral pattern, anatomical location, radio-graphic appearances and histologic features as follows:

Table 3

Tumors based on the gender of predilection

Male Female
Ameloblastoma Adenomatoid odontogenic tumor
Ameloblastic fibroma  
Ameloblastic fibro-odontoma Squamous odontogenic tumor
Ameloblastic odontoma  
Calcifying epithelial odontogenic tumor Odontogenic myxoma
Odontoma Calcifying odontogenic fibroma
Benign cementoblastoma  

Clinical features

Ameloblastomas may be present over a wide age range but are usually diagnosed in the 4th and 5th decades of life, although they can occur in children or the elderly. About 80% of tumors occur in the mandible, of which some 70% arise in the molar region and ascending ramus, 20% in the premolar region, and 10% in the incisor region. In the maxilla, most of these also occur in the molar region but about 15% involves the antrum.

The tumor is slow growing and in the early stages may be asymptomatic and discovered as an incidental finding. As the tumor enlarges the patient may become aware of a gradually increasing facial deformity and expansion of the jaw bone (Figure 1A, B). The enlargement is usually bony hard, non-tender, and ovoid or fusiform in outline but in advanced cases, egg-shell crackling may be elicited due to thinning of the overlying bone. However, perforation of bone and extension of the tumor into soft tissues are late features. In the maxilla, even large tumors may produce little expansion as the lesion can extend into the sinus and beyond. Teeth in the area of the tumor may become loosened, but pain is seldom a feature.

Radiographically, the ameloblastoma appears most commonly as a multiloculated radiolucency (Figure 2A, B). Roots of teeth involved by the tumor show varying degrees of resorption. As the tumor enlarges it may become associated with an unerupted tooth, particularly an impacted third molar, and the appearances may mimic those of a dentigerous cyst. Less frequently, ameloblastomas present as a single unilocular radiolucency indistinguishable from an odontogenic cyst.


There are six histologic subtypes: follicular, plexiform, acanthomatous, granular cells, basal cell and desmoplastic. These can be found combined or isolated and not related to prognosis of the tumor. The two main patterns are anastomosing epithelial strands and fields or discrete epithelial islands. The former pattern is called the plexiform (Figure 3) type, the others the follicular (Figure 4A). Both may occur within the same lesion. The follicles consist of a central mass of loosely connected, angular cells resembling the stellate reticulum of the normal enamel organ, surrounded by a layer of cuboidal or columnar cells resembling ameloblasts. The nuclei of the latter are situated away from the basal ends of the cells, and this is described as reversed polarity. The follicles are separated by varying amounts of fibrous connective tissue stroma. A variety of changes can occur within the stellate area of the follicles and these include cystic breakdown, squamous metaplasia, and granular cell change. The tumor epithelium in the plexiform type is arranged as a tangled network of anastomosing strands and irregular masses, each of which shows the same cell layers as for the follicular pattern. Thus, each strand or mass is bounded by columnar or cuboidal cells resembling ameloblasts, while the central area is occupied by stellate reticulum-like cells. Microcyst formation is commonly seen.

When extensive squamous metaplasia, often associated with keratin formation, occurs in the central portion of a follicular ameloblastoma, the term ‘acanthomaotus ameloblastoma’ is used (Figure 4B).


The therapeutic approach to the ameloblastoma is still a controversy. There are problems to determine incidence, management or recurrence rate. Not every ameloblastoma has the same destructive potential or recurrence tendency. For unilocular cystic lesions in young patients, curettage or enucleation is effective treatment. Solid lesions show high recurrence rates (50–90%) necessitating tumor excision or partial resection of the jaw bone. There seems to be more consensus in the management of ameloblastomas in children, due to the psychological impact of an aggressive resection, and its relationship with growth and function.

Key points on ameloblastoma are given in Box 2.

Unicystic Ameloblastoma

Unicystic ameloblastoma, a variant of ameloblastoma first described by Robinson and Martinez in 1977, refers to those cystic lesions that show clinical and radiologic characteristics of an odontogenic cyst but on histologic examination show a typical ameloblastomatous epithelium lining part of the cyst cavity, with or without luminal and/or mural tumor proliferation. This type of ameloblastoma typically presents in a younger age group than other variants of ameloblastoma (2nd to 3rd decade) and occurs predominantly in the mandibular third molar region.

Radiographically, it appears as a well-defined unilocular radiolucency, usually associated with an unerupted tooth, and is indistinguishable from a dentigerous cyst. The pathogenesis of the lesion is unknown. Although it may represent ameloblastomatous change in a dentigerous or other type of odontogenic cyst, the possibility that it was a grossly cystic ameloblastoma from the outset cannot be excluded.

Odontoameloblastoma (OA)

This is an extremely rare mixed odontogenic tumor appearing within the maxillary bone, with both epithelial and mesenchymal components. It is also known as ameloblastic odontoma, although the term ‘odontoameloblastoma’ (OA) was included in the 1971 WHO classification and seems to be more appropriate due to the behavior of the tumor like an ameloblastoma rather than as an odontoma. Thoma et al described in 1944 the first case, ‘it is an ameloblastoma in which focal differentiation into an odontoma appears to have taken place’.

Clear-Cell Odontogenic Tumor (Carcinoma)

This is a rare jaw tumor that some consider as a carcinoma because of reported metastases. The histogenesis is unknown, although it is believed to be derived from odontogenic epithelium because of its primary occurrence in the jaws. Clear-cell odontogenic tumor (carcinoma) has been described mostly in women above the age of 60 years. It may cause some pain.

Radiographically, the lesion is lucent and either unilocular or multilocular. This rare lesion has an aggressive biologic behavior. Metastases to lung and regional lymph nodes have been reported.

Microscopically, nests and cords of clear cells are seen. Some peripheral palisading may be present.

Differential diagnosis would include clear-cell variant of calcifying epithelial odontogenic tumor, central mucoepidermoid carcinoma, metastatic renal cell carcinoma, and poorly fixed ameloblastoma.

Calcifying Epithelial Odontogenic Tumor

The calcifying epithelial odontogenic tumor (CEOT) is a rare, benign epithelial neoplasm, also called ‘Pindborg tumor’. It is an aggressive tumor of epithelial derivation usually associated with an impacted tooth in the mandible body/ramus.

Adenomatoid Odontogenic Tumor

Clinical features

The adenomatoid odontogenic tumor usually presents during the 2nd and 3rd decades of life. The majority of tumors arise in the anterior part of the maxilla (Figure 6A), especially in the canine areas, and there are usually few symptoms apart from a slowly enlarging swelling. Clinical features generally focus on complaints regarding a missing tooth. The lesion usually presents as asymptomatic swelling which is slowly growing and often associated with an unerupted tooth. However, the rare peripheral variant occurs primarily in the gingival tissue of tooth-bearing areas. Unerupted permanent canines are the teeth most often involved in AOT.

Radiographic features

On radiographs it usually appears as a well-defined radiolucency but in some cases calcification within the tumor may produce faint radiopacities (Figure 6B). The lesion is often associated with an unerupted tooth and may simulate a dentigerous cyst (simulating a ‘target’ like appearance).


Lesion is well encapsulated and may be solid or partly cystic; in some cases the tumor is almost entirely cystic. It consists of sheets, strands, and whorled masses of epithelium which in places differentiate into columnar, ameloblast-like cells. The columnar cells form duct or tubule-like structures (hence adenomatoid) with the central spaces containing homogeneous eosinophilic material. These are thought to represent abortive attempts at enamel organ formation. There is very little supporting stroma. Small foci of calcification are scattered throughout the tumor and occasionally tubular dentin and enamel matrix may be seen (Figure 7).

Calcifying Odontogenic Cyst

The calcifying odontogenic cyst (COC) was first described as a distinct entity by Gorlin et al in 1962. This lesion is uncommon and represents about 0.03% of the biopsy lesions and less than 2% of all odontogenic cysts and tumors.

Clinical features

The calcifying cystic odontogenic tumor occurs over a wide age range but is usually seen below 40 years of age. About 75% are intraosseous and either jaw may be involved. The majority, including those located in the gingival or alveolar soft tissues, arise anteriorly to the first permanent molar tooth. The lesion usually presents as a slowly enlarging but otherwise symptomless swelling. The COC normally appears as a painless, slow-growing tumor, affecting equally the maxilla and mandible, with predilection to the anterior segment (incisor-canine area). It generally affects young adults in the 3rd to 4th decade, without gender predilection.

Radiographically, the lesion appears as a well-defined unilocular or multilocular radiolucent area containing varying amounts of radiopaque, calcified material. It may be associated with the crown of an unerupted tooth (Figure 8).

Histologically, the cyst is lined by epithelium which shows a well-defined basal layer of columnar, ameloblast-like cells and overlying layers of more loosely arranged cells that may resemble stellate reticulum. A characteristic feature is the presence within the lining of masses of swollen and keratinized epithelial cells which are usually referred to as ‘ghost’ cells since the original cell outlines can still be discerned. The ‘ghost’ epithelial cells may calcify. Breakdown of the epithelium may release keratinous debris into the supporting connective tissue resulting in a prominent foreign body, giant cell reaction.

Keratocystic Odontogenic Tumor

Keratocystic odontogenic tumor is more universally known as odontogenic keratocyst, but has been renamed as there is sufficient evidence that this lesion actually represents a cystic neoplasm. First described by Philipsen in 1956, the odontogenic keratocyst (OKC) was later designated by the WHO as a keratocystic odontogenic tumor (KCOT) and is defined as ‘a benign uni– or multicystic, intraosseous tumor of odontogenic origin, with a characteristic lining of parakeratinized stratified squamous epithelium and potential for aggressive, infiltrative behavior’. WHO recommends the term ‘keratocystic odontogenic tumor’ as it better reflects its neoplastic nature.

Clinical features

KCOTs comprise approximately 11% of all cysts of the jaws. These occur most commonly in the mandible, especially in the posterior body and ramus regions (Figure 8). They almost always occur within bone, although a small number of cases of peripheral KCOT have been reported. Patients may present with swelling, pain and discharge or may be asymptomatic. Distinctive clinical features include a potential for local destruction and a tendency for multiplicity, especially when the lesion is associated with nevoid basal cell carcinoma syndrome (NBCCS) or Gorlin–Goltz syndrome. In the recent years, published reports have influenced WHO to reclassify the lesion as a tumor.

Several factors form the basis of this decision.


Histologically, these cysts are formed with a stratified squamous epithelium that produces orthokeratin (10%), parakeratin (83%), or both types of keratin (7%). The epithelial lining appears corrugated when viewed under a microscope. A well-polarized hyperchromatic basal layer is observed, and the cells remain basaloid almost to the surface. No rete ridges are present; therefore, the epithelium often sloughs from the connective tissue. The epithelium is thin, and mitotic activity is frequent; therefore, OKCs grow in a neoplastic fashion and not in response to internal pressure. The lumen frequently is filled with a foul-smelling cheese-like material that is not pus but rather collected degenerating keratin (Figure 9AC).

Radiographic features

Radiographically, KCOT presents predominantly as a unilocular radiolucency with well-developed sclerotic borders. These may also present as a multilocular radiolucency or unilocular radiolucency at varying ratio. The multilocular appearance can be more of a unilocular with scalloped borders lacking true compartment formation. Odontogenic keratocysts of the maxilla are smaller in size compared to the mandible. When they are large, they tend to expand bone. No difference in site distribution is seen between unilocular and multilocular cysts. These lesions can also present as a small and oval radiolucency between teeth simulating a lateral periodontal cyst. They can also appear as a radiolucency simulating a residual apical periodontal cyst (Figure 9D).


Clinical features

Odontomas are the most common maxillary tumors, and according to different sources in the literature account for 22–67% of all odontogenic maxillary neoplasms. As to their locations, most are found in the areas of the upper incisors and canines, followed by the antero– and posteroinferior regions.

Complex odontomas are more often found in the area of the second and third lower molars. An increased prevalence of these tumors is observed in children and adolescents, with few differences in relation to patient sex. These lesions are normally diagnosed by routine radiological studies in the 2nd and 3rd decades of life. As regards their pathogenesis, odontomas have been associated with antecedents of trauma during primary dentition, as well as with inflammatory and infectious processes, hereditary anomalies (Gardner’s syndrome, Hermann’s syndrome), odontoblastic hyperactivity, or alterations of the genetic components responsible for controlling dental development.

Radiographic features

Odontomas manifest as a dense radiopaque lesion surrounded by a thin radiotransparent halo. Three developmental stages can be identified, based on the radiological features and degree of calcification of the lesion at the time of diagnosis:

Compound odontomas show an irregular radiopaque image with variations in contour and size, composed of multiple radiopacities corresponding to the so-called denticles. In the complex type of lesion radiopacity is not specific; rather, a disorganized, irregular single or multiple mass is identified (Figure 10).

Basal Cell Nevus Syndrome or Gorlin-Goltz Syndrome

Basal cell nevus syndrome (BCNS) was first described by Gorlin and Goltz in 1960, is an inherited disorder, with a high penetration and variable phenotype expression. It has a low incidence, around 1 in 56,000 persons. Its etiology is unknown, although the latest genetic studies relate this syndrome to a disturbance at gene level of chromosome 9 (9q22.3–q31), which is passed from one generation to the next, although there are only sporadic cases due to spontaneous mutation.

Clinical features

It is characterized by a series of associated manifestations, the most common being maxillary keratocysts and cutaneous basal cell carcinomas, and other less frequent ones which can be present, such as cardiac disturbances such as persistent ductus arteriosus, characteristic facies in the form of mandibular prognathia, frontal and parietal prominence, marked superciliary arches, wide bridged nose and hypertelorism, skeletal (brachymetacarpalism of the fourth and fifth fingers, vertebrae problems, costal synostosis or bifid ribs), skin (dermoid cysts, lipomas), neurological (congenital hydrocephalus, calcification of the cerebral falx, learning difficulties), sight such as blindness, congenital cataracts, strabismus), hormonal (hypogonadism) or associated with other malignant neoplasias. The appearance of pitted depressions, due to the lack of corneous strata in the palms of the hands and soles of the feet, is the only pathognomonic data which has been described in the literature regarding this condition.

Ameloblastic Fibroma, Ameloblastic Fibrodentinoma and Ameloblastic Fibro-odontoma

The ameloblastic fibroma is a rare benign tumor in which both the epithelial and mesenchymal elements are neoplastic. In ameloblastomas only the epithelium is neoplastic. It is important to differentiate the lesion from ameloblastoma since, unlike the latter, it does not exhibit a locally invasive growth pattern.


The tumor consists of proliferating strands and clumps of odontogenic epithelium lying in highly cellular fibroblastic tissue resembling the dental papilla of the developing tooth. The epithelial component shows a peripheral layer of cuboidal or columnar cells which encloses a few stellate reticulum-like cells (Figure 11). The appearances are similar to ameloblastoma but the stellate cells are much less abundant and cyst formation is unusual. In some lesions dentin may be present and such tumors may be designated ameloblastic fibrodentinoma. The dentin is usually poorly formed and includes entrapped cells. Tubular dentin is rare.

Literature review

Tumors previously classified as dentinomas are now thought to be examples of the ameloblastic fibrodentinoma. The ameloblastic fibro-odontoma is a tumor which shows further inductive changes leading to the formation of enamel. Although the ameloblastic fibroma and fibrodentinoma are benign neoplasms, it is probable that the ameloblastic fibro-odontoma is a hamartoma. Histologically, it is difficult to distinguish from a developing complex odontome, to which it is probably closely related.

Key points on ameloblastic fibroma are given in Box 3.

Differential diagnosis is given in Box 4.

Benign Cementoblastoma

Cementum is a modified form of bone and, with the exception of the cementoblastoma, disorders of the jaws containing cementum-like tissue are now classified as lesions of bone. The cementoblastoma is still classified as an odontogenic tumor because of its unique association with the root of a tooth. Cementoblastoma is classified as an odontogenic tumor because of its unique association with the root of a tooth. This is one characteristic feature that differentiates it from osteoblastoma of bone.

Odontogenic Myxoma

These are uncommon, benign neoplasms arising from mesenchymal odontogenic tissue which are locally invasive neoplasm consisting of rounded, angular cells lying in abundant myxoid stroma.

Odontogenic Fibroma

This jaw tumor is considered a neoplasm that is derived from periodontal ligament or pulp-related fibroblasts. It is a tumor of adults and appears as a well-defined radiolucency in either jaw. It is not, however, particularly aggressive, and it infrequently recurs after simple curettage.

Benign Non-Odontogenic Tumors

The primary disease processes that give rise to swellings and tumors of the oral cavity include cysts, mucous extravasations and retention in the minor salivary glands, foci of granulation tissue and inflammation, abscesses and connective-tissue proliferations that are well-defined or encapsulated, as well as infiltrative sarcomas. Both epithelial and connective-tissue disease processes can present as tumors. From a clinical perspective the three most important defining characteristics of any soft tissue swelling are location, coloration, and palpable nature.


Certain diseases tend to occur in specific sites to the exclusion of others, as given in Table 5.

Table 5

Soft tissue swellings according to site

Site Type of lesion
Lips and buccal mucosa Fibroma, mucocele, mesenchymal tumor, salivary tumor
Gingiva Parulis, pyogenic granuloma, peripheral fibroma, peripheral giant cell granuloma, peripheral ossifying fibroma, gingival cyst, peripheral odontogenic tumors
Palate Abscess, torus, salivary gland tumor
Dorsum of the tongue Fibroma, granular cell tumor, pyogenic granuloma
Ventral aspect of the tongue Mucocele, ranula, lymphoid aggregates, lymphoepithelial cyst, osteocartilaginous choristoma


It is dependent upon the tissues present in the mass and the depth of the lesion. In general, yellow-appearing lesions are comprised of lymphoid tissue or adipose tissue, red swellings are vascular, blue swellings are mucinous or venous, and brown swellings contain melanin or blood pigments. Lesions with normal mucosal pink coloration are generally composed of fibrous tissues or some other tissues lying deeper in the connective tissues (Table 6).

Table 6

Soft tissue swellings according to their color

Color Soft tissue mass
Blue-purple Hemangioma, varix, hematoma, peripheral giant cell granuloma, mucocele, Kaposi sarcoma
Red Hemangioma, pyogenic granuloma, Kaposi sarcoma
Brown Nevus, hematoma, seborrheic keratosis, Kaposi sarcoma, melanoma
Black Melanoma
Yellow-orange Lymphoid aggregates, lymphoepithelial cyst, lipoma, granular cell tumor

Palpable nature

Based on the consistency they can be grouped as shown in Table 7.

Table 7

Soft tissue swellings according to their consistency

Palpation characteristic Swelling
Soft, fluctuant Mucocele, ranula
Developmental cysts
Gingival cysts
Soft non-fluctuant Lipoma
Organized mucocele
Firm fixed Mesenchymal tumors
Salivary adenomas
Adnexal skin tumors
Firm movable Granular cell tumor
Seborrheic keratosis

Human papillomavirus (HPV) and oral lesions given in Box 5.

Classification based on the tissue of origin is given in Table 8.

Table 8

Classification based on the tissue of origin

Epithelial Papilloma
Connective tissue Fibroma
Giant cell fibroma
Peripheral ossifying fibroma
Vascular tissue Hemangioma
AV fistula
Carotid body tumor
Lymphatic origin Lymphangioma
Neural tissue Neurilemmoma
Muscular origin Leiomyoma
Bone origin Osteoblastoma
Osteoid osteoma
Benign osteoblastoma
Desmoplastic fibroma of bone
Cartilaginous Chondroblastoma

AV: Arteriovenous.

Squamous Papilloma

A benign epithelial proliferation induced by HPV in most cases; several subtypes have been identified, especially HPV-6 and 11.

Verruca Vulgaris (Oral Warts)

Infection of mucosal epithelium by members of the human papillomavirus group—usually HPV-2, 4, 6, or 11.

Verrucous Hyperplasia

Lesion with an unknown etiology, even though tobacco (smokeless) association has been reported, the role of HPV is unclear and is even hypothesized to be a possible precursor to verrucous carcinoma.

Jan 12, 2015 | Posted by in Oral and Maxillofacial Radiology | Comments Off on 13: Tumors of Orofacial Region
Premium Wordpress Themes by UFO Themes