RPG Rev Pós Grad 2011;18(3):176-81

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Expansive lesion of the anterior mandible in child: a case report of calcifying cystic odontogenic tumorMARCO ANTONIO TREVIZANI MARTINS*, MANOELA DOMINGUES MARTINS*, MÁRCIA MARTINS MARQUES**, SANDRA KALIL BUSSADORI***, CESAR ANGELO LASCALA****

* Department of Oral Pathology of School of Dentistry of Federal University of Rio Grande do Sul (UFRGS) – Porto Alegre/RS, Brazil. ** Department of Endodontics of School of Dentistry of São Paulo University (USP) – São Paulo/SP, Brazil. *** Rehabilitation Science Post Graduation Program of Nove de Julho University (UNINOVE) – São Paulo/SP, Brazil. **** Department of Radiology of School of Dentistry of São Paulo University – São Paulo/SP, Brazil.

AbstrAct

The calcifying cystic odontogenic tumor is an un-common lesion that occurs in both jaws. This odontogen-ic neoplasm is generally asymptomatic, found either in routine radiographic examination or when causing bone expansion. The purpose of this report was to describe a case of calcifying cystic odontogenic tumor involving mandible in a 9-year-old girl, as well as discuss the im-portance of careful diagnostic procedures for the correct final diagnosis and establishment of the most appropri-ate treatment of this uncommon odontogenic lesion that can affect the patients of the pediatric group.

Descriptors

Odontogenic tumor. Odontogenic cysts. Diagnosis, Differential.

introDuction

The calcifying cystic odontogenic tumor (CCOT) was formerly known as the calcifying odontogenic cyst or Gorlin cyst, but recently was reclassified according to the new World Health Organization (WHO) classifi-cation. This new terminology was due to the neoplastic nature of the lesion, which was previously classified as a cystic entity1. It is a rare odontogenic tumor constitut-ing 0.37 to 2.1% of all odontogenic tumors5,12. Most of the lesions occur centrally within the jawbones, but pe-ripheral (extraosseous) lesions of gingiva or edentulous alveolar ridge are reported in 12 to 20% of cases8.

The CCOT normally appears as a painless, slow-growing tumor8. Previous studies3,5,18 showed no predi-lection for either the maxilla or mandible; however, other studies indicated the mandible as a more affected area7,8. It tends to occur in the anterior portions of both jaws3,6.

Patient age varies widely from infancy to elderly, with no gender predilection3,9. The mean age of patients with CCOT is 30.3 years, with most cases occurring between the second and third decades of life3. Most studies have recorded a pronounced peak frequency in the second de-cade, but others have reported a bimodal age distribution with a second peak in the sixth/seventh decade3,10.

Histologically, CCOT is a tumor characterized by the proliferation of fibrous connective tissue wall lined by an odontogenic epithelium of variable thickness with ghost cell masses that undergo calcification3,6,18.

Radiographic appearance is usually a unilocular ra-diolucency with possible radiopacities observed within the lesion3,6. The presence of calcification, ranging from tiny flecks to large masses, is an important radiographic feature detected in about half of all cases. Root resorption and root divergence are common. The tumor may be associated with impacted teeth in one-third of the cases. Patients experience alveolar bone expansion in a half of the cases4,14,16.

Treatment of CCOT involves enucleation. Recurrence is unusual and depends on the completeness of tumor removal4,14.

The purpose of this report was to describe a case involving the lateral incisor and canine of the right man-dible in a 9-year-old girl. A discussion of the diagnosis, radiographic and microscopic findings, emphasizing its distinction from other bone lesions is presented.

cAse report

A 9-year-old girl was referred to the Stomatology post-graduation clinic complaining of loose tooth and

Corresponding address: Manoela Domingues Martins Rua Ramiro Barcelos, 2492, sala 503 – Santana CEP 90035-003 – Porto Alegre/RS, Brazil Phone: (55) 51 3308-5011 E-mail: manomartins@gmail.com

a painless swelling of the mandible, which has been present for one month. The patient medical history was non-contributory. The anamnesis revealed no oth-er symptoms. Physical examination revealed a healthy condition of the patient. Extraoral examination showed a mild face asymmetry in right anterior region of the mandible with no inflammation signs. Intraorally, there was a well-defined and firm swelling located at the right anterior mandible. The lesion extended from the right lateral incisor to right canine, expanding the lingual and buccal bone cortex (Figure 1A). The mucosa overlying the lesion was intact, non tender, but exhibited a purplish area. All teeth involved, although presenting little mobil-ity, were vital. The lesion caused a separation of incisor and canine, with nonspecific rotation (Figure 1A). The radiographic examination comprised a dental panoramic (Figure 1B), mandibular occlusal (Figure 1C) and pe-riapical (Figure 1D) radiographs. The images revealed a well-defined unilocular radiolucency delimited by radiopaque sclerotic border at the right mandible ex-tending from lateral incisor to canine of the same side (Figure 1B-D). The adjacent teeth (incisor and canine)

Figure 1 - Clinical and radiographic aspects of de CCTO. Intraoral view showing expansion of the right mandibular anterior vestibule (A). Panoramic (B), occlusal (C) and periapical (D) radiographs showing a well-defined unilocular radiolucency of the anterior man-dible. Note the displacement of right mandibular permanent canine and lateral incisor roots.

BA

C D

BA

C D EFigure 2 - Surgical aspects. The clinical aspects of the lesion surface after the incision (A). The well-defined fibrous tissue detached entirely resulting in an excisional biopsy (B). The bone aspect after the lesion removal (C). The immediate post-operatory view showing the complete closure of the surgical area (D). Macroscopic aspect of the biopsy specimen (E).

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were divergent with no signs of root resorption. The clin-ical and radiographic differential diagnosis included cen-tral giant cell granuloma, keratocystic odontogenic tu-mor and ameloblastoma. Thus, an incisional biopsy was planned under local anesthesia; however, during the sur-gical approach, the lesion detached entirely resulting in an excisional biopsy (Figure 2). The postoperative course was uneventful. The biopsy material was fixed in a 10% formalin solution and submitted to histopathological analysis. Figure 3 shows the histopathological findings for the tumor. A cystic lesion with a fibrous capsule lined by odontogenic epithelium of varying thicknesses was observed (Figure 3). Columnar cells resembling amelo-blasts (Figure 3A) and cuboidal cells forming a well-de-fined basal layer (Figure 3B) were present. In areas, the epithelium presented loosely arranged cells. Hyaline, eo-sinophilic and partially mineralized material (dysplastic dentine) were occasionally seen in the connective tissue adjacent to the epithelium (Figure 3A). Toward the lu-men, epithelial cells without nucleus presented a round enlarged morphology slightly eosinophilic. These large ballooning cells, known as ghost cells, were a prominent

feature. The ghost cells showed varying degrees of dys-trophic calcification (Figure 3B). The lesion was diag-nosed as a calcifying cystic odontogenic tumor. Further clinical (Figure 4A) and radiographic (Figure 4B) evalu-ation demonstrated that the teeth have returned to correct position. Radiographic examination showed a total bone formation (Figure 4B). No recurrence was detected in a clinical and radiographic follow-up of 18 months.

Discussion

The CCTO is a mixed epithelial and mesenchymal od-ontogenic tumor that has a wide range of clinical and radio-logical appearance, which can simulate (or possibly coexist with) a different number of pathological conditions1. Based on these data, a detailed evaluation is necessary to establish a precise final diagnosis and an adequate treatment.

CCTO incidence varies in literature; however, all studies indicate that it is a rare lesion2,4. In fact, in a recent study, Fernandes et al.5 were able to detect only 12 cases (3.5%) of CCTO in 340 cases of odontogenic tumors in a Brazilian population.

A

B

Figure 4 - Clinical (A) and radiographic (B) aspects 18 months after the excision of the lesion. The teeth have returned to the correct posi-tion. Panoramic radiograph showing bone regeneration in the area (B).

A

B

Figure 3 - Photomicrograh showing a tumor with cystic aspect lined with epithelium exhibiting areas of well-defined columnar basal layer (A - hematoxylin and eosin, x10). Dentinoid and dysplastic dentin (D) is seen in the epithelial lining (A - hematoxylin and eosin, x10). Clusters of ghost cells (G) and dystrophic calcification foci are present in the epithelial surface (B - hematoxylin and eosin, x20).

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The general clinical aspects (e.g. age, lesion local-ization and symptoms) of this case are in consonance with those previously described in the literature for CCTO2,3,7. Although the incidence of CCTO is mostly in the second decade of life, this lesion may occur at any age. In this case, it occurs in the first decade of life. The lesion appeared in the anterior portion of the mandible, and the literature indicates the anterior portions of both jaws as the most common sites for CCTO3-5,7-9,16.

In the present case, the CCTO presented a slow growing and a painless swelling that caused clinical teeth dislocation, common features of several benign intraosseous lesions. The radiographic examination demonstrated a solitary, well-circumscribed radiolucent area which displaced adjacent teeth. No calcifications were identified on plain radiographs. The absence of fever, lymphadenopathies and erythemas (intraoral and extraoral), associated with the presence of teeth vitality, excluded the diagnosis of inflammatory lesions. Due to the rarity of CCTO, the preoperative diagnosis is diffi-cult to be done based only on clinical and radiographic features of the lesion. From a clinical and radiographic point of view, differential diagnosis included benign ra-diolucent lesions, such as central giant cell granuloma (CGCG), keratocystic odontogenic tumor (KCOT) and ameloblastoma11,13. Based on the fact that these lesions require different treatments, incisional biopsy and his-topathologic analysis were necessary for the final diag-nosis. In this case, incisional biopsy was planned under local anesthesia; however, when the lesion was accessed, it detached entirely resulting in an excisional biopsy. The diagnosis of CCTO was histologically determined.

Radiographically, CCTO generally appears as a uni-locular lesion with well-defined margins in which calcifi-cations may be observed. The radiographic aspects of the lesion described in this paper showed similar characteris-tics to those of the current literature3,4,6,14,16 although calci-fications were not observed on plain film. The absence of evident mineralized tissue on radiographs was also report-ed in other studies in which calcified bodies were micro-scopically found. In fact, calcifications had been detected in about half of all CCTO3,4. Some reports have indicated that computed tomography (CT) may be more successful than plain film radiography in depicting such calcification, because such calcifications may be obscured in plain ra-diographs by superimposition of anatomic details14,16.

The CGCG is one of the most important lesions to be discussed in the differential diagnosis, because it has a predilection for women at any age, and most cases oc-cur before the age of 30 years. Moreover, CGCG affects

the anterior part of the jaw and 70% of the cases in-volve the mandible. Usually, this lesion may be present as a unilocular or multilocular radiolucency, often with poorly distinguished borders17.

Other important lesion to be considered in the differen-tial diagnosis is the KCOT, that occurs in a wide age range, most commonly in the second and third decade, more fre-quently in men. Furthermore, this lesion affects mandible twice as often as the maxilla. It was previously known as the odontogenic keratocyst. The name was changed to re-flect its neoplastic nature1,2,4. Ameloblastoma, specially the unicystic type, is seen in the second or third decades of life, and must be included in the differential diagnosis. The KCOT and ameloblastoma show slow growing; however, present local invasive behavior and high rate of recurrence if not treated with more aggressive procedures1. On the other hand, the CCTO and CGCG exhibit slow growing, but they are not invasive, thus the treatment generally in-volves only the enucleation of the lesion1.

The definitive diagnosis of CCTO is made his-tologically due to the lack of pathognomonic clinical characteristics and radiological features4. The most notable histological features of this pathologic entity include a cyst lining demonstrating clear cells known as ghost cells with a propensity to calcify and hyaline areas suggestive of immature or dysplastic dentine. The histological aspects described in this case are in accordance with literature1,4,6,8,10,14,18. The microscopic features confirm that calcified masses may not nec-essarily appear on radiographic examination even though they may be found microscopically.

The CCTO should be conservatively treated by surgi-cal enucleation with curettage because recurrences are very uncommon. A follow-up period of at least 10 years is, there-fore, recommended9,10,14,15. Most of the recurrent cases have occurred over five years following initial treatment. Maybe in this pediatric population the CCTO could be more aggres-sive, thus this case not only must be closely accompanied, but also has to be divulgated in the dental pediatric care field in order to aware the pediatricians of the possibility of oc-currence of such pathological entity in children.

Fortunately, after a surgical conservative treatment, normal healing and absence of recurrence has been ob-served in a follow-up of 18 months. Although CCTO is an uncommon odontogenic lesion, it can affect the patients of the pediatric group. Careful diagnostic procedures and adequate interpretation of clinical, radiographic and his-tological findings are crucial for the correct final diagno-sis and establishment of the most appropriate treatment.

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resumo

Lesão expansiva em região anterior de mandíbula em criança: relato de caso de tumor odontogênico cístico calcificante

O tumor odontogênico cístico calcificante é uma lesão incomum que ocorre em ambos os maxilares. Esse tumor odontogênico é geralmente assintomático, sendo diagnosticado quando observado em exames radiográficos de rotina ou quando causa expansão óssea. O objetivo deste trabalho foi descrever um caso de tumor odontogênico cístico calcificante envolvendo mandíbula em uma menina de nove anos de idade, assim como realizar uma discussão sobre a importância de procedimentos diagnósticos cuidadosos para o correto diagnóstico final e o estabelecimento do tra-tamento mais apropriado para essa lesão odontegênica incomum que pode afetar paciente do grupo pediátrico.

Descritores

Tumores odontogênicos. Cistos odontogênicos. Diagnóstico diferencial.

references

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Received in: 21/1/11 Accepted in: 12/4/11

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Martins MAT, Martins MD, Marques MM, Bussadori SK, Lascala CA. RPG Rev Pós Grad 2011;18(3):176-81.