OD ON TO GE NI C
TU M OR S
INTRODUCTION
Tooth formation is a complex process that involves both epithelial and connective tissues.
There are three major tissue components involved in odontogenesis:
Enamel organ
Dental papilla, and
Dental follicle
A group of neoplasm and tumor like malformation arising from cells of these odontogenic apparatus and their remnants are known as odontogenic tumor
As they arise from the tissues involved in teeth formation, they are unique to the jaws.
They are a heterogeneous group of lesions of diverse clinical behavior and histopathologic types, ranging from hamartomatous lesions to malignancy.
CLASSIFICATION OF ODONTOGENIC TUMOR
Based on the tissue of origin
Epithelial origin
• Ameloblastoma
• Adenomatoid odontogenic tumor
• Pindborg Tumor
• Squamous odotogenic tumor
Mesenchymal origin
• Odontogenic myxoma
• Central odontogenic fibroma
• Cementoblastoma
Mixed epithelial and mesenchymal origin
• Ameloblastic fibroma
• Compound and complex odontoma
EPITHELIAL ODONTOGENIC TUMOR
Ameloblastoma
Best known epithelial odontogenic tumor
Slow growing locally aggressive epithelial odontogenic tumor.
Though considered benign it has a locally aggressive growth pattern.
70% of cases undergo malignant transformation, and up to 2%
metastasize to other sites
Microscopic appearance of this tumor resemble ameloblast with no formation of calcified material.
Most common site is posterior mandible but may arise in maxilla and any other part of the jaw.
Most common age of occurrence is between 20-50 yrs
ETIOPATHOGENESIS
• Exact etiology not known.
• But number of factors have been enumerated like
Trauma,
Inflammation,
Nutritional deficiencies,
Non-specific irritation from extractions,
Dental caries
• At the molecular level, the genetic factors involved in tooth development,
morphogenesis, cyto-differentiation, and tooth patterning have been associated
with development of ameloblastoma.
Table 1 Clinicohistological types of ameloblastoma.
Clinical, histologic, and radiographic features of the histological subtypes of ameloblastoma
Type of Ameloblast oma
Synonyms Salient Feature Conventional
Radiological feature
Histopathological Features
Benign Solid/Multi cystic
Conventional/Classical
Ameloblastoma • Mean age: 36 years
• Male > female
• Slightly higher in mandible
• Unilocular radiolucency
• Multilocular radiolucency
• Unerupted tooth
• Root resorption
Cystic,
acanthomatous, granular, basaloid, spindle, clear cell, hemangiomatous
Unicystic Cystogenic
ameloblastoma Dentigerous type:
Mean age: 16.5 years M>F
Non-dentigerous type:
Mean age: 35.2 years M<F
• Unilocular radiolucency
• Multilocular radiolucency
• Unerupted tooth
• Unilocular radiolucency
• Multilocular radiolucency
Luminal (plexiform unicystic,
intraluminal), mural
Type of Ameloblasto ma
Synonyms Salient Feature Conventional Radiological feature
Histopathological Features
Peripheral Extraosseous/
soft tissue ameloblastoma
Mean age: 51 years Male > female Slightly higher in mandible
Exophytic
Mean size 1.3 cm
Saucerization Not applicable
Desmoplastic Ameloblastoma with
pronounced desmoplasia
Mean age: 41.6 years Female = male
Maxilla = mandible
Mixed radiolucent/
radiopaque Root resorption
Hybrid
Desmoplastic osteoplasia Malignant
Metastasizing Malignant
ameloblastoma Mean age: 34.4 years Male > female
Slightly higher in mandible
Distant sites: lungs and other areas
Same as
solid/multicystic Same as
solid/multicystic
Type of
Ameloblastoma Synonyms Salient Feature Conventional
Radiological feature Histopathologi cal Features Primary
ameloblastic carcinoma
Not applicable Mean age: 53 years Male > female Higher in mandible (posteriorly)
Ill-defined multilocular radiolucency
Foci of calcification
Not applicable
Secondary ameloblastic carcinoma (intraosseous)
Carcinoma ex intraosseous ameloblastoma
Rapid growth, 7th decade
Male > female Slightly higher in mandible
Ill-defined multilocular
radiolucency Not applicable
Secondary ameloblastic carcinoma (peripheral)
Carcinoma ex intraosseous ameloblastoma
Male = female Alveolar bone resorption
Foci of calcification Inter radicular
radiolucency
Not applicable
MASSIVE AMELOBLASTOMA OF MAXILLA
RADIOGRAPHIC PATTERNS OF AMELOBLASTOMA
Unicystic type: This appears as a unilocular radiolucency resembling a cyst. However, unlike cyst, it causes a break or discontinuity in the peripheral cortex and may even show trabeculae within the lumen.
Spider-web pattern: This is the most common appearance, where the lesion is seen as a large radiolucent area with scalloped borders. From the center of the lumen coarse strands of trabeculae radiate peripherally, giving rise to a gross caricature of a spider.
Soap-bubble pattern: This lesion is seen as a multilocular radiolucency with large compartments of varying sizes, giving rise to the soap-bubble appearance, or a multi-chambered or multi-cystic 'bunch of grapes' appearance.
Honeycomb or solid pattern: This is also called a beehive pattern. These are tumors that have not undergone cystic degeneration. Hence, multiple small radiolucencies are seen surrounded by hexagonal or polygonal thick-walled bony cortices, giving rise to a honeycomb appearance.
a. Unicystic ameloblastoma. b. Spider web pattern of ameloblastoma
c. Soap Bubble Pattern d. Tennis racket pattern
There is a pronounced tendency for ameloblastomas to cause extensive root resorption, either blunting of root apex/knife-edge root resorption or multiplanar or sharp root edges.
Tooth displacement, displacement or destruction of inferior alveolar canal, and displacement of the sinus membrane are the common findings in ameloblastoma.
Comprehensive treatment protocol of ameloblastoma 1. Small lesions
Excisional biopsy → Bone curettage
2. Unilocular or multilocular cystic lesions Marsupialization and strict follow-up → Effective: enucleation + bone curettage Ineffective: marginal or segmental resection 3. Solid lesions
With clear boundaries → Enucleation + Bone curettage With unclear boundaries → Marginal or segmental resection
ADENOMATOID ODONTOGENIC TUMOR
It was initially thought to be a variant of ameloblastoma and was therefore referred to as “ameloblastic adenomatoid tumor” or “adenoameloblastoma.”
In 1969, Philipsen and Birnsuggested the term AOT.
WHO classification (2005) defines AOT as “being composed of odontogenic epithelium in a variety of histoarchitectural patterns, embedded in a mature connective tissue stroma characterized by slow but progressive growth
Histologically characterized by a very distinct capsule surrounding the tumor and structure resembling duct within the epithelium
The most likely source of the AOT are the residues of dental lamina and the odontogenic epithelium adjacent to the reduced enamel epithelium.
CLINICAL FEATURES
It is a slowly growing lesion
It commonly occur in maxillary anterior region.
Most commonly seen in young females( usually in second decade of life).
The lesions are typically asymptomatic, commonly involving an impacted tooth and may be discovered during routine radiographic examination.
It may appear as a painless hard swelling and can cause cortical expansion and displacement of the adjacent teeth.
There are 3 variants of adenomatoid odontogenic tumour –
the Follicular type (accounting for 73% of cases) is a central intrabony lesion associated with an unerupted tooth;
the extra follicular type (24% of case) is also an intra-osseous lesion but unrelated to an unerupted tooth and
the peripheral type is a rare variety (3% of cases) that arises in gingival tissue .
RADIOGRAPHIC FEATURES
The continuous slow growth of the lesion may cause cortical plate expansion leading to a painless hard swelling.
On radiograph this lesion is present as extensive well defined circumscribed , corticated unilocular expansile radiolucent lesion.
Displacement of adjacent teeth with usually no discontinuity of the cortical margin .
Flakes of radioopaque calcified tissue are also present.
Treatment
The surgical management of this tumor should be enucleation along with the associated impacted tooth and simple curettage.
SQUAMOUS ODONTOGENIC TUMOR
• Rare lesion composed of multiple island of squamous epithelium
• The epithelium does not show ameloblast like feature as seen in ameloblast.
• Equal predilection for maxilla and mandible
• No distinct radiographic feature
• Radiolucent area may resemble periodontal bone loss or inflammatory disease Treatment
Conservative surgical excision
MESENCHYMAL ODONTOGENIC TUMOR
Odontogenic Myxoma
• Myxomas are tumor consist of loose cellular connective tissue containing little collagen and large amount of intercellular substances
• The odontogenic myxoma is generally considered to be a rare neoplasm unique to the jaws.
• In the international histological classification of odontogenic tumors, odontogenic myxoma (OM) is defined as a benign odontogenic tumor of mesenchymal origin that is locally invasive and consists of rounded and angular cells lying in abundant mucoid stroma.
• It comprises 3–6% of all odontogenic tumors
Clinical Features
• The most common age of occurrence of this tumor varies from 22.7 to 36.9 years. It is rarely seen in patients younger than 10 years and older than 50 years of age.
• Posterior Mandible is more frequently affected than the maxilla.
• Most often they are first noticed as a result a slowly growing increasing swelling or asymmetry of the affected jaw.
• Growth may be rapid with infiltration of neighboring soft tissue structures.
• OM of the maxilla may be asymptomatic or on examination, it may present as heaviness, swelling of cheek or palate, malocclusion or loosening of teeth, and also displacement of teeth.
• Lesions are generally painless, and ulceration of the overlying oral mucosa occurs only when the tumor interferes with dental occlusion.
• When the maxillary sinus is involved, it often fills the entire antrum. They may still involve the palate, orbit, and nasal cavity, causing symptoms associated with this structures
Radiographic feature
• Radiographically, the tumor presents as a unilocular or multilocular radiolucent lesion with well- defined borders.
• The multilocular pattern with fine bony trabeculae within its interior structure expressing a
“honeycombed”, “soap bubble” or “tennis racket” appearance.
• Unilocular appearance may be seen more commonly in children and in the anterior parts of jaws.
• Displacement of teeth is a relatively common finding, root resorption is rarely seen and the tumor is often scalloped between roots.
Treatment
It varies from curettage to radical excision.
Complete surgical removal can be difficult as the lesion is not encapsulated especially in the maxilla because the myxomatous tissue infiltrates adjacent bone tissue as well as close proximity of vital structures and more complex anatomy
IMAGES OF ODONTOGENIC MYXOMA
CENTRAL ODONTOGENIC FIBROMA
• Composed of mature fibroblastic tissue admixed with nest and strands of odntogenic epithelium.
• Uncommon odontogenic tumor.
• Slowly growing and not a aggressive lesion
• They are usually small lesion but may cause root resorbtion
• Radiographically characterized by well defined unilocular radiolucency
CEMENTOBLASTOMA
• In 1927 Dewey was the first to report a benign cementoblastoma
• It is cementum producing neoplasm that get attached to the roots of vital tooth
• It is the only true neoplasm of cementum origin.
• The prevalence of this neoplasm is less than 1% to 6.2%.
Clinical Features
Seen in younger individuals. 73% of cases seen in individual younger than 30 yrs Slightly more common in males than females
Commonly seen in association with vital mandibular premolar or molar.
Pain is a frequent complain
But sometimes it may be present as painless diffuse swelling Radiographic features
The spectrum of radiographic appearance of cementoblastoma depends on its degree of mineralization. Early-stage lesions generally appear more radiolucent
Later the cementoblastoma demonstrate a pathognomic appearance – A well defined radiopaque mass surrounded by a radiolucent halo that incorporates the root of the tooth
RADIOGRAPHIC IMAGES OF
CEMENTOBLASTOMA
DIFFERENTIAL DIAGNOSIS
The Differential diagnosis includes
cementoma,
osteoblastoma,
odontoma,
condensing osteitis,
periapical cemental dysplasia, and
hypercementosis.
Osteoid osteoma or
Atypical osteosarcoma
Treatment
Enucleation of the cyst with removal of offending teeth
MIXED ODONTOGENIC TUMORS
Ameloblastic Fibroma
Non encapsulated tumor that is composed of mesenchymal tissue resembling dental papilla and small islands of odontogenic epithelium resembling dental lamina
Most common age below 20 yrs. Common in very young children.
Most common site is mandibular premolar and molar region.
Radiographically a radiolucent lesion that may be unilocular, multilocular, well defined or ill defined radiolucency.
Surgical excision is the treatment of choice.
COMPOUND AND COMPLEX ODONTOMAS
• The term odontome was coined by Paul Broca in 1867.
• Broca defined the term as tumors formed by the overgrowth or transitory of complete dental tissue
• Non aggressive lesion that is more likely to be a hamartoma rather than a true neoplasm
• Odontomas result from the growth of completely differentiated epithelial and mesenchymal cells that give rise to ameloblasts and odontoblasts
• These cells in turn form variable amounts of enamel and dentin and pulpal tissue of the odontoma.
CLINICAL FEATURES
The etiology of odontomas remains unknown, although local trauma, infection, and genetic factors have been suggested.
Erupted odontomas, especially compound type are rare to seen.
Odontomas constitute about 22% of all odontogenic tumors of the jaws.
Approximately, 10% of all odontogenic tumors of the jaws are compound odontomas.
In Compound odontome all dental tissues are represented in a more orderly pattern than in the complex odontome so that the lesion consists of many tooth-like structures.
Complex odontome is a malformation in which all dental tissues are represented, individual tissues being mainly well formed cut occurring in more or less disorderly pattern.
The incidence of compound odontome ranges between 9 and 37% and the complex odontome is between 5 and 30%.
Odontomas are discovered during the second and third decades of life.
The compound odontoma is slightly more common than the complex odontoma which in turn is more common than the ameloblastic odontoma.
The majority of odontomas in the anterior segment of the jaws are compound composite in type (61%),
whereas the majority in the posterior segment is complex composite in type (34%).
• Interestingly both type of odontomas occurred more frequently on the right side of the jaw than on the left, (compound 62%, complex 68%).
• The compound composite odontome most frequently occurred in incisor cuspid region of the upper jaw in contrast to the complex odontome which were commonly found in molar and premolar region of the mandible
• Odontomes commonly occur in permanent dentition and are rarely reported in association with primary teeth
• Commonly cause delay in eruption of the teeth
• Treatment Surgical removal
GARDNER’S SYNDROME
Gardner’s syndrome (GS) is an autosomal dominant disorder localized to a small region on the long arm of chromosome 5 (5q21–22)
Gardner’s Syndrome is a variant of familial adenomatosis polyposis (FAP) with a triad consisting of
• Polyps of the colon,
• Multiple osteomas and
• Surface tumors of soft and hard tissue.
The intestinal polyps have a 100% risk of undergoing malignant transformation, therefore early identification of this disease is very important.
There are several symptoms of Gardner’s syndrome in the oral and peri oral structure, which can be discovered during routine dental examination.
Clinical Features
The intestinal polyps of the disease typically occur prior to puberty and become generalized in the 20–40-year age group.
These multiple polyps can be observed at any location in the gastrointestinal tract, particularly in the distal colon, and must be completely removed due to the high rate of transformation to adenocarcinoma.
Soft-tissue lesions such as fibromas, neurofibromas, keloids, sebaceous cysts, leiomyomas, and lipomas are also observed.
Desmoid tumors are considered locally invasive, non-malignant, and non-encapsulated and may occur in the skin of the anterior abdominal wall or intra-abdominally.
They display no malignant potential and have a slow growth pattern.
These lesions occur in approximately 10% of patients and are three times more common in women.
Oral and Perioral findings
Dental abnormalities are present in 30–75% and osteomas in 68–82% of GS patients.
The osteotomas are generally located in the paranasal sinuses and mandible, display slow growth, and vary from a slight thickening to a large mass.
Osteomas predominantly affect the mandible and maxilla, but can additionally affect the skull and long bones.
Osteomas are an essential component of GS, forming a slight thickening to a large mass that may affect all parts of the skeleton.
The frontal bones are the most frequent osteoma site.
Exosteoses osteomas, also called peripheral osteomas, and enosteoses osteomas can be palpable.
In the mandible, two types of osteomas occur:
Central or
Lobulated.
Centrally located osteomas are characteristically near the roots of the teeth.
Lobulated types arise from the cortex and most commonly observed at the mandibular angle.
Seventy percent of patients display dental anomalies such as
Impacted or unerupted teeth,
Congenitally missing teeth,
Supernumerary teeth & hypercementosis,
Dentigerous cysts, fused molar roots, long and tapered molar roots,
Hypodontia, Compound odontomes,
and Multiple caries
