Large ameloblastic fibro-odontoma in a 7-year-old girl with analysis of 108 cases.

BACKGROUND: Odontogenic tumors such as ameloblastic fibro-odontoma (AFO) are rare conditions in children and are often asymptomatic. AFOs are found by routine clinical and radiological examination or when they cause obvious intra- or extra-oral swelling.
MATERIALS AND METHODS: A case of an AFO in a 7-year-old girl is described, and 107 cases from the literature and this report are analyzed.
RESULTS: The total of 108 cases revealed the average age at presentation of AFO to be 6.3 years in boys and 9.6 years in girls. There was a slight male predilection and AFO lesions most often occurred in the posterior mandible. AFO was almost always associated with an unerupted tooth or teeth.
CONCLUSIONS: While the recurrence rate of AFO was found to be 5.5%, long-term postoperative clinical and radiological follow-up is advised to ensure no future signs of aggressive recurrence.

INTRODUCTION

Ameloblastic fibro-odontoma (AFO) is one of the mixed radiolucent and radiopaque odontogenic tumors. It is relatively rare. Studies indicate that AFO is seen ranging from 0.3% to 1.7% of oral pathology biopsy specimens submitted as possible odontogenic tumors.[12] AFO was originally termed ameloblastic odontoma before the current nomenclature. Only a few studies exist regarding the characteristics of AFOs as most case reports take the form of single patient publications.[3] This study aimed to review cases of AFO reported consecutively in the literature between the years 1967 and 2015 with the addition of a new case.

CASE REPORT

An otherwise healthy 7-year-old girl was referred by her dentist because of swelling of the left side of the mandible. An asymmetric facial swelling was obvious on extraoral examination [Figure 1]. There was no history of trauma or local infection. Intraoral examination revealed normal mucosa overlying the lesion and the absence of the left mandibular first and second molar teeth [Figure 2]. A distinctive hard bulge was palpable in the vestibule of the left mandible molar region. The mouth opening was normal and there was no pain or other symptoms apart from the swelling. Panoramic radiography [Figure 3] and cone-beam computed tomography scan [Figures 4 and 5] both revealed a large well-defined radiolucent area that contained several radiopaque structures of varying sizes and shapes. The lesion extended from the first molar to the coronoid process and the condylar neck. The borders of the lesion were well circumscribed and the lesion had displaced the developing second molar tooth bud down to the inferior border of the mandible.

Figure 1

Extraoral swelling of the left side of the mandible

Figure 2

Missing or absent molars of the left side of the mandible

Figure 3

Preoperative panoramic radiograph showing large mixed radiolucent and radiopaque lesion of the left ramus and body of mandible

Figure 4

Preoperative cone-beam computed tomography scan revealing large mixed lesion of he left ramus and body of mandible

Figure 5

Preoperative cone-beam computed tomography scan coronal view of mixed lesion

The lesion was enucleated using an intraoral approach under general anesthesia. During the same procedure, tooth numbers 75 and 37 were also extracted. The tumor measured 10 cm × 4 cm × 4 cm in size [Figure 6] and was submitted for histopathological examination. The samples were stained with hematoxylin and eosin. A large number of epithelial strands and islands of odontogenic epithelium were found. The hard tissue component consisted of dentin and enamel. Histopathological examination [Figures 7 and 8] confirmed the clinical and radiological diagnosis of AFO. Clinical and radiological follow-up [Figure 9] was continued over 24 months and the postoperative course was uneventful with no recurrences to date.

Figure 6

Resected specimen delivered using an intraoral approach

Figure 7

Ameloblastic fibro-odontoma with odontogenic epithelium (1) and odontogenic stroma (2) (H and E, ×20)

Figure 8

Ameloblastic fibro odontoma exhibiting areas of odontogenic epithelium (1) and (2) (H and E, ×40)

Figure 9

Panoramic radiograph taken 6 months following surgery with healing of intraosseous lesion of the left ramus and body of mandible

MATERIALS AND METHODS

A search was conducted using Medline and Scopus databases using the search words AFO and odontogenic tumors. This yielded a total of 1254 hits which included many lesions other than AFO, such as ameloblastic fibroma (AF), ameloblastic fibrodentinoma, ameloblastic fibrosarcoma, and odontoma. The search was restricted to AFO and reports including the other diagnoses were removed. The criteria for inclusion in this review were reports describing radiographic features consistent with AFO, histologic features consistent with AFO, and minimum follow-up of 6 months following removal of the lesion. Any report or study failing to mention any of the above inclusion criteria was excluded. This yielded a total of 107 cases which together with the newly reported case of the 7-year-old girl comprising 108 cases forming the database of this review.

RESULTS

A summary of the findings of AFO reports is presented in Table 1. AFO was found to be a benign tumor of children with the average age at presentation being 6.3 years in males and 9.6 years in females. AFO had a female: male ratio of 1:1.62. Typically, AFO lesions were located in the posterior region of the mandible in 60% of cases. Almost all lesions, 94 of 106 (89%), were associated with the crown of an unerupted tooth or teeth. Clinically, AFO was usually painless and was characterized by asymmetric swelling of the face and delayed tooth eruption. Radiological features of AFO included a cyst-like lesion with radiopaque areas resembling a developing odontoma. The recurrence rate in this review of 108 cases was only 6 recurrent cases or 5.5% [Tables 1 and 2].

Table 1

Summary of reported cases of ameloblastic fibro-odontoma

Table 2

Characteristics of 108 ameloblastic fibro-odontoma lesions

DISCUSSION

In defining AFO, the World Health Organization lists it as a rare odontogenic tumor with the histologic features of AF in conjunction with the presence of dentin and enamel.[73] Histopathologically, the tumor is composed of both soft and hard tissues. The soft tissue component is composed of epithelial strands and small islands of odontogenic epithelium associated with a primitive appearing myxoid connective tissue which resembles the dental papilla [Figures 7 and 8]. The hard tissue component consists of foci of enamel and dentin.[74]

Studies have shown that AFO is usually not aggressive and can be treated surgically without removal of the adjacent teeth.[4368717075] A few studies suggest that AFO can behave aggressively with multiple recurrences.[2476] There had been suggestions that a primarily benign AFO can undergo malignant transformation to ameloblastic fibrosarcoma.[58777879] Therefore, it is important to continue the follow-up of AFO lesions for several years.

CONCLUSIONS

AFO is a rare benign mixed odontogenic tumor. Normally, AFO is found at the average age of 9 years in females and 6 years in males. The prognosis is good. The correct diagnosis is based on clinical, radiological, and histopathological findings. AF and complex odontoma must be considered in the differential diagnosis. The treatment of choice is to remove tumor surgically usually by enucleation.

In this newly reported case, the AFO tumor was enucleated and the area of the left posterior mandible healed uneventfully without complications. Clinical and radiological follow-up has continued for 24 months with no signs of recurrence. Follow-up must be continued on a regular basis for several years. The patient in this case report is now receiving orthodontic treatment and remains under vigilant surgical follow-up.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.