A. Lesions related to the apices of teeth



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Radiographic Interpretation:

It is the study of a radiograph or reading it. It includes reporting any variation from the normal or any abnormal findings observed, and recommending any further investigations if needed.

[ I ] RADIOLUCENT LESIONS

A. Lesions related to the apices of teeth (Periapical RL- unilocular)

1. Radicular cyst (infected or not).

2. Periapical granuloma.

3. Periapical abscess (chronic).

4. Periapical cementoma. (Periapical cementoosseous dysplasia).

5. Scar or surgical defect.

6. Other lesions occurring periapically

B. Lesions related to the side of the teeth (Lateral RL – unilocular)

1. Lateral periodontal cyst.

2. Periodontal abscess.

C. Lesions occurring between the roots of teeth (inter-radicular RL)

1. Lateral radicular cyst.

2. Lateral periodontal cyst.

3. Globulomaxillary cyst.

4. Traumatic bone cyst.

5. Incisive canal cyst. (Nasopalatine canal cyst).

D. Lesions related to the crowns of unerupted teeth or impacted teeth (pericoronal RL- uni or multilocular)

1. Follicular space.

2. Dentigerous cyst.

3. Mural ameloblastoma.

4. Odontogenic keratocyst.

5. Adenomatoid odontogenic tumor (Adenoameloblastoma).

6. Calcifying epithelial odontogenic tumor ( Pindborg tumor).

7. Ameloblastic fibroma.

8. Other lesions.

E. Unilocular lesions in the midline of the maxilla:

1. Incisive canal cyst (Nasopalatine cyst).

2. Median palatine cyst.

F. Unilocular lesions lateral to the midline of the maxilla

1. Globulomaxillary cyst.

2. Residual cyst.

G. Well-defined solitary cyst-like RL (not necessarily contacting teeth)

1. Residual cyst.

2. Traumatic bone cyst.

3. Primordial cyst.

4. Odontogenic keratocyst.

5. Ameloblastoma.

6. Central giant cell granuloma.

7. Odontogenic fibroma (central).

8. Calcifying epithelial odontogenic tumor (Pindborg tumor).

H. Multilocular RL with well-defined borders

1. Multilocular cyst.

2. Ameloblastom.

3. Central giant cell granuloma.

4. Odontogenic myxoma.

5. Odontogenic keratocyst.

6. Central hemangioma.

7. Cherebism.

8. Anneurysmal bone cyst.

9. Calcifying epithelial odontogenic tumor.
[ I ] Radiolucent Lesions

[A] Lesions Related to the Apices of Teeth (Periapical Lesions):

1] Periapical Granuloma:

Periapical granuloma by far represents the most common type of pathologic radiolucency. These lesions represent about 70% to 90% of all pulpoperiapical lesions. Periapical granuloma is the result of a successful attempt by the periapical tissues to neutralize and confine the irritating toxic products escaping from the root canal, therefore, the offending tooth is non-vital and asymptomatic including an absence of sensitivity to percussion.


  • Radiographic Features:

    • A well defined small round or oval RL surrounding the apex of the tooth which may have a thin radioopaque border (hyperstotic or sclerotic border).

    • A periapical granuloma cannot be differentiated from a radicular cyst by the radiographic appearance alone although cysts are larger than granulomas and any RL larger than 1.6cm in diameter will most probably a radicular cyst.

  • Differential Diagnosis:

1. Radicular cyst.

2. Periapical scar or surgical defect.

3. Periapical cemental dysplasia (PCD) primary stage.

4. Chronic periapical abscess.

5. Traumatic bone cyst (TCB).

2] Radicular Cyst:

The radicular cyst is the second most common pulpoperiapical lesion and is the most common of all odontogenic cysts. It is classified as an inflammatory cyst because it is thought that inflammatory products initiate the growth of the epithelial component. It originates in a pre-existing periapical granuloma. As the epithelial nests start to proliferate, the central cells start to degenerate and liquefy due to ischemia leading to the formation of a liquid-filled cavity lined with epithelium (cyst).


  • Radiographic Features:

    • Radiographic features of a radicular cyst are similar to those of a granuloma; round or oval RL, well defined and corticated (RO border).

    • Almost any periapical RL larger than 1.6 cm is most likely a radicular cyst.

    • Almost 20% of apices associated with radicular cysts show resorption.

    • A radicular cyst may enlarge and cause expansion of the cortical plates demonstrating a crackling sound as the cortical plate becomes thinned.

    • Large cysts may involve a whole quadrant.

    • If the cyst becomes infected, the RO border disappears and the tooth develops all the painful symptoms of an abscess.

  • Differential Diagnosis:

1. Periapical granuloma.

2. Periapical scar or surgical defect.

3. Periapical cemental dysplasia (PCD) primary stage.

4. Chronic periapical abscess.

5. Traumatic bone cyst (TCB).

3] Periapical abscess:



a. Acute periapical abscess: No radiographic features will be associated with the lesion because of its sudden onset and rapid course that no bone has yet been resorbed. The infection and inflammatory exudates will frequently force the tooth slightly from it socket creating an increased or widened periodontal membrane space around the apex.

b. Chronic periapical abscess: It develops from an improperly managed acute periapical abscess or from a previously existing asymptomatic periapical radiolucent lesion like a periapical granuloma, radicular cyst or periapical scar.

  • Radiographic Features:

    • Chronic periapical abscess appears radiographically as a diffuse radiolucency that varies in size depending on the primary lesion in which the infection occurs.

    • Loss of lamina dura at the apex is evident.

    • The initial lesion may have caused expansion of the cortical plate.

    • If the chronic abscess remains untreated, it frequently forms a sinus tract permitting pus to drain to the surface. When drainage is established, pain is relieved.

  • Differential Diagnosis:

1. Infected radicular cyst.

2. Osteomyelitis.

4] Periapical Scar or Surgical Defect:



Periapical Scar: It is composed of dense fibrous tissue at the apex of pulpless tooth in which the root canals have been successfully treated. It represents a previous granuloma, cyst or abscess whose healing has terminated at the formation of dense scar tissue rather than bone.

Surgical Defect: A surgical defect in bone is an area that fails to fill in with bone after apical root resection (apicectomy procedures) especially when both labial and lingual plates have been destroyed. It is composed of dense fibrous tissue at the apex of a pulpless tooth.

  • Radiographic Features:

    • The periapical scar and the surgical defect both appear radiographically as a well-defined radiolucency that is more or less round and smoothly contoured.

    • The tooth is asymptomatic and the associated radiolucency may show decrease in size with time or remains constant.

    • They are both associated with a successful endodontically treated tooth or with a history of previous apical surgery.

  • Differential Diagnosis:

1. Periapical granuloma.

2. Radicular cyst.

5] Periapical Cementoma: (Periapical cementoosseous dysplasia OR Periapical cemental dysplasia)



        • Periapical cementoosseous dysplasia OR periapical cemental dysplasia (primary stage), PCOD or PCD, is the most common fibroosseous lesion. It occurs most commonly in the mandible where the periapical region of the incisors is the most frequently involved site.

        • PCD is usually seen in middle-aged black females and the lesion may be solitary or multiple. It is associated with teeth having vital pulps, thus it is completely asymptomatic and small in size seldomly exceeding 1cm in diameter. PCD has the following stages of development:

a. Primary or early stage: Osteolylic or fibroblastic stage and is radiographically radiolucent.

b. Intermediate stage: Appears as a radiolucent area containing radioopaque foci.

c. Final or mature stage: Calcified stage where the lesion appears completely radioopaque radiographically, well defined, homogenous and in most cases surrounded by a thin RL rim or border.

  • Radiographic Features:

    • Well-defined rounded radiolucency which is not corticated.

    • Associated with vital teeth and are usually multiple affecting lower incisor teeth.

    • Lesions are usually small, up to 1cm in diameter.

  • Differential Diagnosis:

1. Periapical granuloma.

2. Traumatic bone cyst.

Other periapical radiolucencies may also include:

a) Periodontal disease:

Advanced periodontal bone loss may cause severe destruction of bone around the roots of teeth creating a radiolucency in which the tooth may appear to floating (endo-perio lesion).



b) Traumatic bone cyst (simple bone cyst-solitary bone cyst):

Traumatic bone cyst is classified as a false cyst because it is not lined by epithelium. Although its etiology is unknown, history of trauma is usually reported. Although typically the lesion is a large radiolucency occupying the mandibular premolar-molar region in the tooth-bearing area, above the inferior alveolar canal and extending between the roots of teeth producing a scalloped appearance, it may also appear as a periapical radiolucency. The teeth involved in this radiolucency are vital, the lamina dura is intact and the lesion itself appears well-defined, round to oval in shape and usually occurs in patients under 25 years old.




  • Differential Diagnosis:

1. Radicular cyst.

2. Periapical cemetal dysplasiea (primary stage).

c) Osteomyelitis:

  • Occasionally a periapical abscess develops into an acute or chronic osteomyelitis. Osteomyelitis is an infection of bone that involves all three components: periosteum, cortex and marrow. It usually occurs in the mandible and appears as an ill-defined radiolucency (chronic osteomyelitis) that may resemble a periapical abscess or cyst, however its borders are usually ragged (moth eaten).

  • Such an appearance is characteristic of infections in bone and caused by irregular extensions of the inflammation into marrow spaces. If a sequestrum is present and large enough, it shows as a radioopacity within the radiolucency. A sinus tract is usually seen draining pus and opening into the mucosa or skin.

d) Non-radicular cysts:

On occasion, non-radicular cysts may be projected as well defined radiolucencies over the apices of teeth. The most common of these cysts are the incisive canal cyst, median palatine cyst and primordial cyst. The teeth associated with such radiolucencies are usually vital and by changing the angulation, the radiolucency can be projected away from the apex.



e) Malignant tumors.

f) Eosinophilic granuloma.

[B] Lesions Related to the Side of the Teeth (Lateral RL):

1] Lateral Periodontal cyst:



i. Lateral (inflammatory) periodontal cyst:

It occurs in the periodontal ligament usually near the alveolar crest. It is thought to arise as the result of a periodontal disease that affects the tooth. Pocket contents may be the irritant that stimulates its formation.



ii. Lateral (developmental) periodontal cyst:

It is an unusual odontogenic cyst whose cause is unclear and has several theories for its formation (e.g., remnants of reduced enamel epithelium or dental lamina, an early dentigerous cyst of an erupted tooth, a primordial cyst or from the rests of Malassez in the periodontal ligament). It occurs along the lateral surface of the root of a vital tooth or in an interradicular position and has a high predilection for the mandibular canine-premolar area. It is usually asymptomatic.



  • Radiographic Features:

    • Appears as a unilocular round to oval radiolucency that is well-defined and usually corticated.

    • Seen along the lateral surface of the root or between the roots of teeth.

    • Size is usually small (less than 1cm in diameter).

  • Differential Diagnosis:

1. Lateral radicular cyst.

2. Odontogenic keratocyst.

3. Periodontal abscess.

2] Periodontal abscess:

Periodontal abscess is a rapidly processing destructive lesion that usually originates in a deep soft tissue pocket when the coronal portion of the pocket becomes occluded or when a foreign material becomes lodged between the tooth and the gingiva. Clinically, there is pain and swelling present in the area and the associated tooth is usually vital. If the lesion persists, a radiographic picture appears.


  • Radiographic Features:

    • An ill –defined radiolucent region appears lateral to the surface of the root.

    • A bridge of bone may be present over the coronal aspect of the lesion.

  • Differential Diagnosis:

1. Lateral radicular cyst.

2. Odontogenic keratocyst.

[C] Lesions Occurring Between the Roots of Teeth (Inter-radicular RL):

1] Lateral radicular cyst:

Lateral radicular cysts may occur when a sizable accessory canal opens to the lateral root surface. Associated teeth have no vital pulps. When the cyst becomes infected, pain and swelling occur and the offending tooth becomes sensitive to percussion.


  • Radiographic Features:

    • Appears as a small well-defined radiolucency adjacent to the root surface.

  • Differential Diagnosis:

1. Lateral periodontal cyst.

2. Odontogenic keratocyst.

3. Periodontal abscess.

2] Lateral periodontal cyst:

Previously discussed.

3] Globulomaxillary cyst:

It is currently believed that the globulomaxillary cyst is an odontogenic cyst occurring in the globulomaxillary reign. This theory replaces the previous concept that these cysts are fissural cysts originating from epithelial inclusions trapped between the maxillary process and the globular process during embryonic development. It is asymptomatic and pulps of involved teeth are vital. As it becomes larger and expands the cortical plate buccally, the patient may complain of swelling or pain especially if it becomes infected.


  • Radiographic Features:

    • The classic picture of the globulomaxillary cyst is of an inverted pear or tear shaped, well-defined radiolucency between the roots of the maxillary lateral incisor and canine.

    • It causes divergence of the roots of the lateral and canine.

    • Usually small in size.

    • The lamina dura around the roots of both teeth is intact.

  • Differential Diagnosis:

1. Lateral radicular cyst.

2. Lateral periodontal cyst.

3. Primordial cyst.

4. Central giant cell granuloma.

5. Traumatic bone cyst.

4] Traumatic bone cyst:

Previously discussed. Rarely, TBC may occur in the interradicular bone. In these cases it will cause little destruction of the bone just inferior to the apex and interradicularly.

5] Incisive canal cyst: (Nasopalatine cyst)

The nasopalatine canal cyst is the most common non-odontogenic cyst. It arises from the embryonic epithelial remnants of the nasopalatine duct. The lesion is usually painless and the most frequent complaint is a swelling posterior to the palatine papilla. The maxillary central incisors are vital.



  • Radiographic Features:

    • The lesion appears as a well-defined RL in the maxillary central incisors area (between the roots) that is usually corticated.

    • Often, the anterior nasal spine is superimposed on the superior portion of the cyst producing a heart-shaped radiolucency.

    • The cyst can extend till about 2cms in diameter.

    • The lesion may cause displacement of the roots of the central incisors and palatal expansion.

  • Differential Diagnosis:

1. Large incisive foramen.

2. Radicular cyst.

[D] Lesions Related to the Crowns of Unerupted or Impacted Teeth-Pericoronal Radiolucencies:

1] Follicular space-Dental follicle: (Pericoronal space)

The crowns of unerupted teeth are normally surrounded by a dental follicle – a soft tissue remnant of the enamel organ which is necessary for tooth eruption.


  • Radiographic Features:

    • The dental follicle appears radiographically as a homogeneous well-defined radiolucent halo surrounding the crown of an un-erupted tooth.

    • The space is corticated representing compact bone that is continuous with the lamina dura. This RL hallow later merges with the periodontal membrane space.

    • Diameter of a normal follicular space varies from one developing tooth to another. In general, diameter less than 2mm will be considered normal. If the pericoronal RL reaches 2.5mm in width on the radiograph, this may be evidence that fluid is collecting within the follicle and pathosis is present in 80% of cases. (Dentigerous cyst).

  • Differential Diagnosis:

  • Dentigerous cyst.

2] Dentigerous cyst:

    • After the radicular cyst, the dentigerous cyst is the most common odontogenic cyst and it is the most common pericoronal radiolucency. Dentigerous cysts are associated with the crowns of unerupted or impacted teeth. The teeth most frequently affected are the mandibular third molars, maxillary canines, the mandibular premolars or an unerupted mesiodens. It has the highest incidence during the second and third decades of life. The cyst varies in size from less than 2cms in diameter to massive expansions of the jaws.

    • If multiple dentigerous cysts are found, the patient should be examined for basal cell nevus syndrome. “Eruption cyst” is a term used to describe a dentigerous cyst in children when it is situated in the soft tissues overlying the unerupted tooth.

  • Radiographic Features:

    • Dentigerous cyst appears as a well-defined radiolucent lesion surrounding the crown of an unerupted tooth.

    • The RL lesion is a unilocular, well-defined and often corticated. The associated tooth is often displaced from its normal position.

    • Dentigerous cyst may cause resorption of adjacent teeth and large cysts may expand and cause thinning of the cortical plates.

    • The cyst usually surrounds the crown evenly but lateral expansion may also occur.




  • Differential Diagnosis:

1. Mural ameloblastoma.

2. Ameloblastic fibroma.

3. Adentomatoid odontogenic tumor (AOT).

3] Mural (Unicystic) Ameloblastoma:

The unicystic or mural ameloblastoma arises from the wall of a pre-existing cyst – usually a dentigerous cyst. It ranks next to the dentigerous cyst as the most frequently occurring pathological pericoronal radiolucency. It usually occurs in a younger age group (early twenties) than ameloblastoma (late thirties).


  • Radiographic Features:

    • Mural ameloblastoma appears radiographically as a well defined corticated radiolucency associated with an unerupted tooth (usually mandibular third molar).

    • The lesion is slowly growing and causes expansion of the cortical plates of bone with the possibility of destruction.

  • Differential Diagnosis:

1. Dentigerous cyst.

2. Ameloblastic fibroma.

4] Odontogenic Keratocyst:

Odontogenic keratocyst represents 5-11% of all jaw cysts. It’s diagnosis depends entirely on its microscopic features and is independent on its location. Aspiration of these cysts yields thick, cheesy, yellow substance. It usually occurs in the mandible and most commonly develop during the second and third decades of life. It has the highest rate of recurrence of any odontogenic cyst. OKC usually occurs as a radiolucency not contacting the teeth but often enough, it is seen as pericoronal radiolucency.


  • Radiographic Features:

    • OKC are often seen as unilocular radiolucencies that are well-defined and corticated, undistinguishable from any other intra-bony cyst.

    • It can appear with scalloped borders or multilocular.

    • It can acquire large sizes causing expansion of the cortical plates and their perforation.

  • Differential Diagnosis:

1. Ameloblastoma.

2. Residual cyst.

3. Traumatic bone cyst.

5] Adenomatoid Odontogenic Tumor (Adenoameloblastoma) AOT:

AOT is an uncommon, benign, non invasive odontogenic tumor. It is a slowly growing lesion that does not infiltrate bone. AOT is more common in the anterior maxilla and is associated with unerupted maxillary canine, lateral incisor and mandibular premolar. AOT is more common in young women under 20 years of age.


  • Radiographic Features:

    • AOT appears radiographically as a well-defined, corticated radiolucency that is related to an unerupted tooth.

    • It has an inclination to displace neighboring teeth rather than root resorption.

    • Continuous slow growth may expand the cortical plates and produce a clinical swelling, but invasion of the soft tissue does not occur.

  • Differential Diagnosis:

1. Dentigerous cyst.

2. Mural ameloblastoma.

6] Calcifying Epithelial Odontogenic Tumor (CEOT):

CEOT is a rare benign tumor that most commonly occurs as a mixed RL-RO lesion. Nevertheless, many occur as a pericoronal radiolucency especially in early stages. It occurs more in the mandibular molar area of middle-aged patients as a slowly growing painless expansion of the jaws. Small lesions are usually asymptomatic.


  • Radiographic Features:

    • CEOT has several radiographic appearances:

a. A pericoronal radiolucency.

b. A pericoronal radiolucency with radioopaque foci.

c. A mixed RL-RO lesion not associated with an unerupted tooth.

d. A “driven-snow” appearance.

e. A dense radioopacity.

    • An often appearance is of a well-defined radiolucent lesion surrounding the crown of an unerupted tooth.

    • It can cause displacement of teeth.

  • Differential Diagnosis:

1. Adenomatoid odontogenic tumor.

2. Ametoblastic fibroma.

3. Intermediate stage of odontoma.

7] Ameloblastic Fibroma:

It is true mixed odontogenic tumor that is not as frequently associated with an unerupted tooth as AOT although both are usually found in the some age group (under 20 years of age). Its most common site is the posterior mandibular area.


  • Radiographic Features:

    • Ameloblastic fibroma appears radiographically as a pericoronal well-defined, corticated radiolucency. It may also appear multilocular not associated with an unerupted tooth.

    • It may cause displacement of adjacent teeth.

    • Large lesions cause expansion of the cortical plates.

  • Differential Diagnosis:

1. Mural ametoblastoma.

2. Adenomatoid odontogenic tumor.

3. Dentigerous cyst.

8] Other Lesions:

Almost any pathologic process can occur surrounding the crowns of unerupted teeth – of these are the following:

a. Odontogenic fibroma.

b. Odontogenic myxoma.

[E] Unilocular Lesions in the Midline of the Maxilla:

1] Incisive canal cyst: (Nasopalatine canal cyst)

Previously discussed. Cyst of the palatine papilla: It is a soft tissue cyst that is not evident radiographically. It may only appear on clinical examination as a nodular fluctuant mass involving the area of the papilla.

2] Median palatine cyst:

It is an uncommon cyst that develops in the midline of the palate posterior to the palatine papilla in the fusion line of the lateral palatine shelves. The patient complains from a painless bulging that is increasing in size in the roof of the palate.


  • Radiographic Features:

    • The median palatine cyst appears as a well defined radiolucency in the midline of the palate.

    • Large cyst may destroy the palate and cause perforation of the cortical plate, consequently the swelling is soft and fluctuant.

  • Differential Diagnosis:

1. Incisive canal cyst.

2. Radicular cyst.

[F] Unilocular Lesions Lateral to the Midline of the Maxilla:

1] Globulomaxillary cyst:

Previously discussed.

2] Residual cyst:

Residual cyst is a radicular, lateral, dentigerous or any other type of cyst that has remained after its associated tooth has been extracted. It occurs in the alveolar process and the body of the jawbones in edentulous areas. The maxilla is more commonly affected than the mandible. It is usually symptomless.


  • Radiographic Features:

    • Residual cyst appears radiographically as a round to oval radiolucency with well-defined borders and corticated.

    • It is small in size and rarely reaches more than 0.5cm in diameter, however it may be large enough to cause jaw expansion and asymmetry.

  • Differential Diagnosis:

1. Odontogenic keratocyst.

2. Primordial cyst.

3. Traumatic bone cyst.

(G) Well-Defined Solitary Cyst-Like RL (not necessarily contacting teeth):

1] Residual cyst:

Previously discussed.

2] Traumatic bone cyst:

Previously discussed as an interradicular radiolucency.


  • Radiographic Features:

    • The lesion is classically located above the mandibular canal and is usually round to oval with well-defined borders.

    • Often, it superior border extends between the roots of teeth giving a scalloped appearance.

    • Lesions usually measure 3cms in diameter but they may extend to involve the whole mandibular body.

  • Differential Diagnosis:

1. Radicular cyst.

2. Primordial cyst.

3] Primordial Cyst:

A primordial cyst is a less common cyst than OKC and is thought to originate from cystic degeneration in the tooth germ before mineralization has been initiated. The tooth germ may be of the regular permanent dentition, thus the tooth does not develop, or a supernumary tooth and the expected number of teeth are present. It occurs more commonly in the second and third decades of life. The mandibular molar area, especially the area distal to the third molar represents the most frequent site of development.


  • Radiographic Features:

    • The radiographic picture of a primordial cyst is non-specific, showing only a well-defined cyst-like radiolucency where a tooth has not developed.

    • It rarely causes cortical expansion.

    • It may produce deflection of adjacent teeth but rarely any root resorption.

  • Differential Diagnosis:

1. Residual cyst.

2. Keratocyst.

3. Traumatic bone cyst.

4. Ameloblastoma.

N.B.: Absence of a tooth without history of extraction favors a primordial cyst.

4] Odontogenic Keratocyst:

Previously discussed.

5] Ameloblastoma (Unilocular):

Ameloblastoma is an odontogenic tumor that is usually described as locally malignant. Unilocular ameloblastoma may be pericoronal or not necessarily contacting teeth.


  • Radiographic Features:

    • Unilocular ameloblastoma appears as well-defined circular radiolucency in the mandibular body area.

    • Expansion of the lesion causes perforation of the cortical plates.

  • Differential Diagnosis:

1. Radicular cyst.

2. Traumatic bone cyst.

3. Primordial cyst.

4. Odontogenic keratocyst.

6] Central giant cell granuloma:

Central giant cell granuloma is a giant cell lesion that occurs most frequently in female patients under 30 years of age. The majority of these lesions are located in the mandible anterior to the first molar area. It has the ability to cross the midline. Parasthesia is common.



  • Radiographic Features:

    • Initially CGCG occurs as a solitary cyst-like well defined radiolucency; as it grows larger, it frequently becomes a soap-bubble type of multilocular radiolucency.

    • The lesion grows slowly by expanding and thinning the cortical plates but seldom perforates into soft tissue.

    • An expanding lesion may cause some migration of teeth and root resorption.

  • Differential Diagnosis:

1. Ameloblastoma.

2. Odontogenic fibroma.

3. Odontogenic keratocyst.

4. Traumatic bone cyst.

7] Odontogenic Fibroma (central):

It is a rare pathologic condition that occurs more commonly in the mandible.


  • Radiographic Features:

    • The radiographic feature of odontogenic fibroma depends on the stage of tumor development. The early stages are seen as a well-defined cyst-like radiolucency that is unilocular and less often multilocular.

    • Calcifications will take place within the lesion resulting in appearance of radioopaque foci.

  • Differential Diagnosis:

  • Radiolucent Stage:

1. Ameloblastoma.

2. Central giant cell granuloma.

3. Odontogenic myxoma.

  • Mixed Stage:

1. Cementomas.

2. Ossifying cyst.

3. CEOT.

8] Calcifying Epithelial Odontogenic Tumor:

Previously discussed.

[H] Multilocular RL with Well-Defined Borders:

1] Multilocular cyst:



  • Multilocular cyst is the most frequently seen pathologic multilocular radiolucency in the jaws. Any cyst that occurs in the jaws could develop multiple compartments, however radicular and fissural cysts are usually unilocular, whereas odontogenic keratocyst, primordial cyst, dentigerous cyst and residual cyst may occur as multilocular cysts.

  • It occurs more frequently in adults. When small, the lesion is asymptomatic, as it increases slowly in size, it may cause displacement of neighboring teeth and expansion of the cortical plates.

  • The botryoid odontogenic cyst: a particular multilocular cyst that gives a “grape bunch” multilocular radiolucent appearance. It is thought to be a variant of lateral developmental periodontal cyst.

  • Differential Diagnosis:

1. Ameloblastoma.

2. Central giant cell granuloma.

3. Odontogenic myxoma.

4. Odontogenic keratocyst.

2] Ameloblastoma:

It is a locally invasive odontogenic tumor that occurs most commonly in the mandible, specifically in the third molar region and ascending ramus. Average age of occurrence is around 40 years of age. Parasthesia of the lip is common.


  • Radiographic Features:

    • The tumor may cast a unilocular cyst-like image in its early stage.

    • Ameloblastoma more commonly shows a multilocular image of the soap-bubble or the honeycomb variety.

    • As it grows, it can cause migration of teeth, tipping and root resorption.

    • In advanced stages, the neoplasm will expand the cortical plates and may frequently erode them and invade the soft tissue.

  • Differential Diagnosis:

1. Odontogenic keratocyst.

2. Odontogenic myxoma.

3. Odontogenic fibroma.

3] Central Giant Cell Granuloma:

Previously discussed.

4] Odontogenic Myxoma:

Odontogenic myxoma is an infiltrative benign tumor of bone that occurs almost exclusively in the jawbones. It occurs more commonly in the mandible (tooth-bearing area) between ages of 25-35 years.


  • Radiographic Features:

    • Odontogenic myxoma may produce several patterns: unicystic, multilocular, pericoronal (less often) and radiolucent-radioopaque (rare).

    • Unilocular type is small and mostly located in the anterior region.

    • Multilocular type is located in the posterior region. Fine intra-lesional trabeculation occur in most of the multilocular lesions producing a soap-bubble, honeycomb or tennis racket pattern.

    • The margins may be well or ill-defined.

    • The tumor may be scalloped between the roots of teeth.

    • It expands the cortical plate and sometimes causes its perforation.

  • Differential Diagnosis:

1. Ameloblastoma.

2. Central hemangioma.

3. Central giant cell granuloma.

5] Odontogenic Keratocyst:

Previously discussed.

6] Central Hemangioma:

Central hemangioma is a benign tumor that rarely occurs in the jaws and is considered dangerous if it does because of the profound bleeding following tooth extraction and jaw fracture. It affects females more than males and occurs more often in young ages in the mandible.

It is a slowly growing tumor that causes asymmetry of the jaw and possible numbness or tenderness and pain. Local hemorrhage may be present around the crevices of teeth which may demonstrate a pumping action. Aspiration from the swelling will produce blood.



  • Radiographic Features:

    • Central hemangioma can produce so many different radiographic images. The most common of which is a round multilocular radiolucency that could be well or ill-defined and gives a soap-bubble or honey-comb appearance.

    • Another form of these lesions can reveal coarse, linear trabeculae that appear to radiate from the center of the lesion.

    • A third appearance is a cyst like RL with an empty cavity and sometimes a hyperstotic border.

    • The lesion will cause resorption of the roots of the involved teeth and expansion of the cortical plates.

  • Differential Diagnosis:

1. Central giant cell granuloma.

2. Anneurysmal bone cyst.

3. Ameloblastoma.

4. Odontogenic myxoma.

7] Cherubism:

Cherubism is an inherited disease (familial history) that occurs in patients between the ages of 2-20 years. It usually starts bilaterally at the rami of the mandible and becomes apparent as painless swellings of the face in these areas. Occasionally the whole mandible is involved. It also commonly affects other bones as the walls of the maxillary sinus, orbital floor, and tuberosity region resulting in an enlargement in these areas producing a cherub-like expression by tilting the eye balls superiorly. Usually by the age of 30 years, the bony architecture returns to normal except for few instances where bone of the ramus retains an appearance that resembles ground glass on radiographic examination.


  • Radiographic Features:

    • The disease is presented radiographically as bilateral multilocular lesions in the ramus of the mandible that are well defined. Sometimes the interlocular bone becomes so indistinct that the multilocular appearance is lost.

    • Cherubism causes severe expansion of the cortical plates but not perforating the cortex. A few posterior teeth may be missing in the disease because of its early development and expanding masses that destroy the tooth buds. The teeth associated with the lesion are usually displaced.

  • Differential Diagnosis:

  • The young age and bilateral jaw expansion together with the cherubic appearance are usually indicative of the disease. However, because non-familial unilateral cases have been reported (fibrous dysplasia), the DD list may include:

1. Hyperparathyroidism.

2. Central giant granuloma.

8] Anneurysmal bone cyst (ABC):

Anneurysmal bone cyst is characterized as being a false cyst because it does not have an epithelial lining. Etiology is unclear. It usually occurs in individuals less than 30 years of age and affects the mandible more than maxilla. The molar regions are the most common sites. It is a slowly growling lesion that causes expansion and thinning of the cortical plates. Aspiration yields blood.


  • Radiographic Features:

    • ABC characteristically appears as a multilocular radiolucency (soap-bubble) that expands the cortex of the posterior mandibular area.

    • Associated teeth may be missing or displaced.

    • It is rarely seen as a unilocular radiolucency.

  • Differential Diagnosis:

1. Central giant cell granuloma.

2. Cherubism (bilateral).

3. Ameloblastoma.

9] Calcifying epithelial odontogenic tumor:



Previously discussed.





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