Case of the Month Archives

COM Sept. 2004 Diagnosis

Impacted Tooth # 3 Associated with Radiolucent/Radiopaque Lesion

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Figure 1

This is a healthy 14-year-old female who presented at Dr. Camran Zafarnia’s dental office for non-eruption of a maxillary right molar.

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Odontoma, whether complex or compound, hamartoma or neoplasm is the most common odontogenic tumor, accounting for 22% of all odontogenic tumors. It is of mixed epithelial and mesenchymal origin. It is usually associated with unerupted teeth (1). It can occur at any age, but is more common in the first two decades with an average age of 14 or 18. It is slightly more common in females and more common in the maxilla, especially the anterior maxilla, than in the mandible. Compound odontomas are more common in the anterior jaws while complex odontomas are more common in the posterior jaws. In about 80% of cases, they are associated with impacted or unerupted teeth. Radiographically, odontomas present as a well-circumscribed radiolucency resembling a dental follicle or dentigerous cyst with one or multiple radiopaque pieces resembling teeth. Compound odontomas tend to occur between teeth and tend to be composed of multiple small tooth-like structures while complex odontomas tend to occur in the posterior jaws and present as a conglomerate mass. Both types are made up of enamel matrix, dentin, cementum, and dental pulp surrounded by a dental follicle or cyst. Histologically, the tooth-like structures are arranged in a uniform manner similar to the normal tooth. The structures in complex odontomas are mixed and disorganized. These lesions are benign and are conservatively treated with simple curettage (2). Recurrence is not described; if it recurs, one must rule out other odontogenic lesions such as COC, ameloblastic fibro-odontoma and others. The clinical and radiographic presentation is consistent with an odontoma, although posterior maxilla is not a common location for odontomas. However, the soft tissue part of the histology was nor supportive of a purely odontoma diagnosis.

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Calcifying odontogenic cyst was first described by Gorlin et al in 1962 (3). It is not a common condition, accounting for only 1% of jaw cysts. This condition represents a spectrum of histologies including a simple cyst, a cyst with an odontoma, a cyst with ameloblastomatous proliferations and a more aggressive solid neoplasm, also known as “ghost cell odontogenic tumor,” known to transformation. It is therefore important to render a specific histological diagnosis. COC is usually an intra-osseous lesion, but is also described on the gingiva alone without a bony component in up to 20% of cases; this is known as peripheral COC. It presents as a well-circumscribed unilocular radiolucency with flecks or masses of radiopaque material. The size and amount of the radiopaque material varies depending on the type of cyst and whether or not it is associated with an odontoma. It can expand bone, displace and resorb teeth. In about one third of cases, COC is associated with unerupted teeth, usually the canine tooth. The most common locations are the anterior jaws in the incisor-canine area. It can occur at any age, but is most common in patients around 33 years of age (3-4); however, the odontoma-associated COCs tend to occur in younger females around the age of 17. The peripheral (gingival) COCs present as gingival swellings indistinguishable from reactive swellings such as peripheral ossifying fibromas. The simple cyst is the most common type and has been identified as an epithelial lined cavity supported by a connective tissue wall. The lining epithelium has a distinct well-defined basal cell layer covered by multiple layers of stellate epithelial cells resembling stellate reticulum. The lining epithelium also has clusters of ghost epithelial cells. The latter can also be present in the connective tissue wall. The lining epithelium may contain calcified material ranging from non-specific calcifications to dentin, cementum (dysplastic or otherwise), or clusters of calcified ghost cells. This cyst may also be associated with an odontoma, usually complex in type, as described in the above discussion on ameloblastic fibro-odontoma. The solid odontogenic ghost cell tumor is the least common, but behaves more aggressively than the others. These lesions are usually conservatively treated by thorough curettage and heal uneventfully (4). The solid type tends to recur and, for that reason, follow-up visits are recommended. With recurrence, a more aggressive treatment is recommended to prevent further recurrence. Neither the age of the patient or the location is supportive of COC. However, the radiograph is. The histology is also not supportive of COC.

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The ameloblastic fibroma is believed to have been described by Kruse in 1891. It is relatively uncommon. It is a benign, slow-growing, expansile, neoplasm or hamartoma of mixed epithelial and mesenchymal odontogenic origin (5-8). Some suggest that this lesion may represent an early stage of an odontoma. However, it behaves like a neoplasm in terms of growth and expansion of jaw bones. It is known to inhibit tooth eruption and is therefore often associated with impacted teeth. It can also displace teeth. Therefore, these lesions can go undetected by parents unless a noticeable expansion occurs or in the case of failure of tooth eruption and displacement of teeth. It is rarely painful. It occurs most commonly in children in the first and second decade of life with an age range of infancy to 42 years of age (5, 6). It has equal gender predilection and is more common in the posterior mandible than in the maxilla. It also occurs more often in the posterior jaws than in the anterior jaws.

Radiographic findings include an impacted/unerupted tooth with a well-defined, usually unilocular radiolucency around the crown of a tooth similar to a dentigerous cyst. It may also present as a radiolucency containing radiopaque material ranging from flecks to small tooth-like structures. Because of the continued slow growth, this lesion can reach very large sizes if left untreated. The histology of ameloblastic fibro-odontoma is made up of mixed epithelial and mesenchymal components. The epithelial component presents in the form of small islands, cords and rosettes of epithelial cells with columnar and palisaded peripheries and with centers that may or may not contain stellate or cuboidal epithelial cells. The mesenchymal component is made up of primitive connective tissue stroma with tooth-like hard material that has features of a complex odontoma. They are benign and well-differentiated neoplasms; for that reason, transformation is rarely described (7).


Conservative curettage and enucleaction is the treatment of choice, and there is a very low recurrence rate (6). The involved tooth is usually extracted. It has a good prognosis.

This patient was treated on an outpatient basis, utilizing an intravenous sedation anesthesia. After achieving local anesthesia, a mucoperiosteal flap was reflected to expose the bone over the area of the edentulous right maxilla. The overlying bone was removed to expose the crown of impacted tooth #3. A bony defect was observed with multiple tooth-like structures as well as a considerable soft tissue component associated with the crown (Fig 2). Luxation of tooth #3 revealed minor movement. Following careful inspection and re-curettage to remove any odontogenic and/or bony pathology, the area was then irrigated copiously and packed open with iodoform gauze. The surgical specimen was sent for histologic evaluation to the Oral Pathology Biopsy Service at the University of Washington. The maxillary pack was removed one week post surgery demonstrating an uneventful postoperative course.

Figure 2. Surgical specimen demonstrating multiple pieces of hard and soft tissue. The hard tissue is consistent with miniature teeth.


  1. Yeung KH, Cheung RC et al. Compound odontoma associated with an unerupted and dilacerated maxillary primary central incisor in a young patient. Int J Paediatr Dent. 2003;13:208-212.
  2. Chang JY, Wang JT et al. Odontoma: a clinicopathologic study of 81 cases. J Formos Med Assoc. 2003;102:876-882.
  3. Gorlin RJ, Pindborg JJ et al. The calcifying odontogenic cyst–a possible analogue of the cutaneous calcifying epithelioma of Malherbe. An analysis of fifteen cases. Oral Surg Oral Med Oral Pathol. 1962;15:1235-1243.
  4. Moleri AB, Moreira LC et al. Comparative morphology of 7 new cases of calcifying odontogenic cysts. J Oral Maxillofac Surg. 2002;60:689-696.
  5. Chang H, Precious DS et al. Ameloblastic fibro-odontoma: a case report. J Can Dent Assoc. 2002;68:243-246.
  6. Friedrich RE, Siegert J et al. Recurrent ameloblastic fibro-odontoma in a 10-year-old boy. J Oral Maxillofac Surg. 2001;59:1362-1366
  7. al-Sebaei M, Gagari E. Ameloblastic fibro-odontoma. J Mass Dent Soc. 2001;50:52-53.
  8. Flaitz CM, Hicks J. Delayed tooth eruption associated with an ameloblastic fibro-odontoma. Pediatr Dent. 2001;23:253-254.
  9. Pindborg JJ. A calcifying epithelial odontogenic tumor. Cancer. 1958;11:838-843.
  10. Cicconetti A, Tallarico M et al. Calcifying epithelial odontogenic (Pindborg) tumor. A clinical case. Minerva Stomatol. 2004;53:379-387.
  11. Asaumi J, Yanagi Y, et al. Assessment of MRI and dynamic contrast-enhanced MRI in the differential diagnosis of adenomatoid odontogenic tumor. Eur J Radiol. 2004;51(3):252-256.

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CEOT or Pindborg tumor is a benign, slow-growing, locally aggressive neoplasm of odontogenic epithelial origin, first described in 1955 by Danish pathologist Pindborg (9). It is an uncommon neoplasm that constitutes less than 1% of all odontogenic tumors. It is frequently misdiagnosed as metastatic neoplasm by our general pathology colleagues; the histology of atypical epithelial cells and amyloid deposition is conducive to over-interpretation. Pindborg tumor is believed to originate from the stratum intermedium of the enamel organ. Three types have been recognized: intra-osseous, peripheral (extraosseous), and clear cell. The latter is a histological type while the former two represent variations in the clinical presentations. This neoplasm is benign but locally aggressive. It is known to occur at any age, but is clustered around 30-50 years of age, with equal gender distribution and a slight predilection for Caucasians. It is more common in the posterior mandible; around 75% of cases occur in this area (10). It is expansile but otherwise asymptomatic. Slightly more than 50% of these lesions are associated with impacted or unerupted teeth. Peripheral or extra-osseous Pindborg tumors have been described mainly on the gingiva. Pindborg is painless and expansile, and is known to displace teeth. The intraosseous type presents as well-circumscribed unilocular or multilocular radiolucency with radiopacity in the form of flecks. The radiographic pattern of “driven snow” has been attached to this lesion. Histologically, it is made up of sheets, islands and small cords of polyhedral epithelial cells with some evidence of cellular and nuclear pleomorphism (9-10). Intercellular bridges are prominent. These cells produce and release amyloid, an unusual substance for a tooth-related neoplasm. Because of the locally aggressive behavior, these lesions are treated by resection or en bloc, sometimes requiring secondary reconstruction. They are known to recur and, for that reason, patients should be placed on annual follow-up visits. Neither the clinical presentation or the histology are supportive of a Pindborg tumor.

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This is an uncommon benign epithelial odontogenic neoplasm. It is believed to be of enamel organ origin and occurs most commonly in the anterior jaws, anterior maxilla twice as common as the anterior mandible (11). It is more common in females (2:1) and tends to occur between 14 and 18 years of age. It can also occur in the posterior mandible, but rarely; it is even more rare in the posterior maxilla. It is expansile in nature but otherwise asymptomatic. It is slow-growing but progressive in nature. About 75% of cases are associated with impacted teeth, resembling a dentigerous cyst. Radiographically, it presents as a unilocular radiolucency, sometimes with flecks of radiopaque material. Histologically, this lesion is made up of epithelial cells arranged in whorls, nests and bundles of spindle-shaped epithelial cells intermixed with duct-like structures lined by a single layer of cuboidal cells. The epithelial component is supported by a thick fibrous connective tissue wall resembling a cystic structure. Sometimes globules of a homogenous material are present which may be amyloid or tooth related hard structure. Because of the non-aggressive nature of this lesion, conservative surgical curettage or enucleation is the treatment of choice (11). It has a good prognosis with an exceedingly low recurrence rate. The age of the patient and the impacted tooth are good for AOT. However, neither the location or the histology are supportive of AOT.