Surgical treatment of cementoblastoma: case report

1. Universidade Federal de Alagoas, Maceió, Alagoas, Brazil
2. Hospital Policlin/Clínica Prof. Dr. Antenor Araujo, São José dos Campos, São Paulo, Brazil

DOI: 10.5935/1676-2444.20200042

Corresponding author

Suellen Fernandes Santana
ORCID 0000-0002-5438-6119
e-mail: suellenfernandes_@hotmail.com

INTRODUCTION

Cementoblastoma is a true, benign and rare odontogenic tumor^(1-9) of mesenchymal origin⁽¹⁰⁾. Arising from cementoblasts proliferation with consequent disorganized deposition of cementlike tissue around the dental roots^{(3, 5, 9, 10)}; comprises up to 6.2% of all odontogenic tumors^(1-3).

This neoplasm usually shows asymptomatic lesions with slow and unlimited growth, which may, in some cases, present cortical bone expansion, leading to painful symptoms and facial asymmetry^{(2, 4-7, 10, 11)}. In most reports, such lesions occur between the second and third decades of life^{(2, 5, 6, 10)} and do not show gender predilection^{(5, 6, 10)}, although some studies report that they preferentially affect men^{(2, 7)}. They affect the posterior mandible more frequently, mainly unilaterally, involving the roots of premolars and molars^{(2, 3, 5-7, 9-12)}.

Radiographically, cementoblastoma is presented as a welldefined radiopaque image, or of mixed density, with a radiolucent halo associated with the tooth root^{(3, 5, 7)}.

In histopathology, we observed a circumscribed tumor composed of cement-like tissue, with cementoblasts dispersed in a mineralized matrix, with the presence of a variable number of basophilic reversal lines and fibrovascularized stroma^{(2, 3, 5-7)}.

The treatment of choice consists of complete surgical excision associated with the removal of the teeth involved^{(2-5, 7)}. However, treatments such as enucleation together with the preservation of the affected tooth⁽⁷⁾, endodontic therapy and⁽²⁾ have also been reported. The cementoblastoma recurrence is considered rare, occurring only in cases where the lesion is not completely removed^{(2, 3, 5, 7)}.

As this is an unusual finding, this report aims to provide information that allows healthcare professionals to refine the diagnosis and treatment of cementoblastoma, debating issues about therapy, proservation and the clinical, radiographic and histopathological aspects from a clinical case of that lesion.

CASE REPORT

Female patient, 24 years old, brown, sought care in a private dental clinic with pain complaints and increased volume in the left mandibular region for about one year. The medical history was not contributory. In addition, changes in the extraoral examination were not found. The intraoral examination showed a single, circumscribed volume in the mandibular region, color similar to the adjacent normal mucosa, involving the second premolar and the first and second lower molars, with expansion of the buccal and lingual cortical plates. The related teeth showed vitality (Figure 1).

FIGURE 1 – Preoperative intraoral clinical aspect showing increased volume in the left mandibular region

Computed tomography (CT) was performed preoperatively; the following aspects were evidenced: hyperdense lesion with a well-defined and rounded hypodense halo, associated with the distal root of the lower second premolar, the roots of the lower first molar, and the mesial root of the lower second molar, without affecting the mandibular canal (Figure 2).

FIGURE 2 – CT showing a hyperdense lesion surrounded by a hypodense halo
CT: computed tomography.

After performing the incisional biopsy, specimen fragments of brownish tissues were obtained, measuring together, 0.5 × 0.5 cm; then, they were submitted to hematoxylin and eosin (HE) staining to histopathological analysis. This, in turn, revealed fragments of benign odontogenic tumor consisting of cementoid and osteoid particles, with sheets and trabeculae of mineralized material, containing cells scattered over the gaps and basophilic reversal lines, surrounded by a stroma of fibrovascular tissue, in addition to the presence of a tiny fragment of mucosa within normal patterns, which complemented the microscopic picture (Figure 3).

FIGURE 3 – Photomicrograph showing areas that resemble braided bone tissue, showing reversal lines

By correlating clinical, radiographic, and histopathological findings, the diagnosis of cementoblastoma was confirmed. After signing the informed consent form, the proposed treatment consisted of enucleation of the tumor mass together with the extraction of the teeth involved and osteotomy of the bone remnant, in order to completely remove the lesion and maintain bone vitality for better healing, besides preventing recurrence (Figure 4).

FIGURE 4 – Fragments of the excised tumor mass associated with the teeth involved

Thirty days after surgery, the affected region presented satisfactory clinical healing. Panoramic control radiography was performed and showed initial signs of bone neoformation.

The patient continued to be followed up, undergoing tests to control her clinical condition. One year after the established treatment, no clinical signs of recurrence were observed (Figure 5).

FIGURE 5 – Intraoral appearance one year after surgery, showing satisfactory repair

Panoramic radiography showed local bone repair. Due to tooth and bone loss in the affected area, the patient was referred for oral rehabilitation treatment (Figure 6).

FIGURE 6 – Postoperative radiographic appearance (one year) showing no recurrence with local bone neoformation

DISCUSSION

Benign cementoblastoma was first described by Dewey, in 1927, and by Noberg, in 1930, as a true cementoma^{(3, 6, 9, 10, 12)}. The 2005 classification of the World Health Organization (WHO) updated the terminology for cementoblastoma^{(1, 12)}. The term benign was removed from the classification because it is an odontogenic tumor that has no malignant counterpart^{(1, 12)}.

Cementoblastoma is a rare and benign odontogenic tumor^{(3, 7, 9)}, of mesenchymal origin⁽¹⁰⁾, resulting from neoplastic cementoblasts proliferation⁽³⁾. Clinically, it presents slow and constant growth^{(1, 3, 5, 6, 12)}. Its size may vary between 0.5 and 5.5 cm in diameter⁽¹⁾, and can cause expansion of the buccal and lingual cortical plates^{(1, 6, 7, 11, 12)}, a characteristic observed in the present case, besides promoting facial asymmetry^{(1, 5, 12)}. Usually, these lesions are found after the report of pain complaints and increased volume in the region, a fact that corroborates this case; however, it is also possible to be clinically asymptomatic^{(1, 3, 5, 6, 12)}.

Cementoblastoma can be less commonly found with displacement of adjacent teeth^{(1, 3, 7)}, pulp involvement⁽³⁾, root resorption^{(1, 3)}, maxillary sinus^{(1, 7)} and orbit floor invasion⁽¹⁾, displacement of the lower alveolar nerve⁽¹⁾, paresthesia^{(3, 12)}, mandibular deformity⁽¹⁾, and pathological fracture^{(3, 12)}.

The tumor does not show a significant gender predilection^{(5, 6, 8, 10, 12)}, although some studies show a higher prevalence in males^{(3, 5, 13)}, which differs from the case reported here because it affects a female patient. Chrcanovic et al. (2017)⁽⁸⁾ performed an analysis of 258 clinical cases and concluded that cementoblastoma occurs more frequently in young patients, as verified in this report – mean age 20.7 years^{(1, 3)}, with occurrence ranging between 6 and 72 years^{(2, 6)}. It commonly affects the mandible^{(1, 2, 6, 7, 9, 10)}, in the region of molars and premolars. In general, the teeth are vital^{(1, 6, 12)}, and the lower first molar is the most affected^{(6, 8, 10-12)}.

The radiographic appearance of cementoblastoma may vary^{(1, 5, 7, 8, 10, 12)}; in its mature phase, a radiopaque mass is observed, surrounded by a thin peripheral sclerotic halo^{(1, 5-8, 10, 12)}. The contour of the roots that are in close contact with the tumor is poorly defined due to the resorption of the root and the fusion of the mass to the tooth^{(1, 6-10)}. CT can be used to define the size, location of the tumor and its relationship with the mental foramen, as well as to assess the degree of root resorption and assist in surgical planning^{(2, 7)}. The CT features contributed to the diagnosis and planning of the reported case.

Microscopic findings demonstrate a neoplasm composed of a calcified mass of cementum-like tissue^{(1, 7, 9, 12)} with basophilic tumor cells, which may exhibit pleomorphism⁽⁷⁾ and a large number of reversal lines. The periphery of the tumor is generally not mineralized and presents active soft tissue cementoblasts in a fibrovascularized stroma^{(1, 7, 9, 10, 12)}. Mitotic figures are uncommon^{(1, 7)}. Such characteristics are compatible with the lesion presented in this report.

Osteoblastoma is the main differential diagnosis of cementoblastoma⁽⁷⁾, however, the association with the tooth root is a diagnostic criterion to differentiate them^{(1, 5-7, 9)}. As it is a rare entity and has characteristics similar to those of other lesions, it is important to consider clinical entities, such as condensing osteitis^{(1, 3)}, hypercementosis^{(1-3, 5, 7)}, complex odontoma^{(1, 5)}, osteoid osteoma^{(6, 7, 9, 12)}, ossifying fibroma^{(1, 7, 12)}, periapical cemental dysplasia^{(1, 3, 5, 7)}, chronic focal sclerosing osteomyelitis^{(5-7, 12)}, flored bone dysplasia^{(7, 12)}, focal sclerosing osteitis⁽¹²⁾, and osteossarcoma^{(6, 9, 12)}.

The treatment of choice for cementoblastoma adopted in the present case was surgical excision of the tumor mass associated with the extraction of the teeth involved^{(2-5, 7)}, since the tissue remaining after surgery may lead to tumor recurrence^{(2, 3, 5, 7)}.

CONCLUSION

Cementoblastoma is a rare neoplasm; therefore, it is important to consider similar clinical, radiographic, and microscopic entities as a differential diagnosis. Recurrences are associated with inadequate treatments, in which the tumor mass is not completely removed. Surgical enucleation of the lesion was the treatment proposed for this case along with the extraction of the teeth involved, a data consistent with the literature. Currently, the patient is undergoing clinical and radiographic monitoring, with no signs of recurrence.

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