A rare case of huge maxillary ameloblastoma in a 3.5 years old girl

Highlights • Maxillary Ameloblastoma.• Resection and reconstruction using buccal pad of fat.• Healing after maxillectomy and reconstruction using buccal pad of fat.


Introduction
Ameloblastoma is a benign locally invasive neoplasm, it is derived from odontogenic epithelium [3]. It's the most common odontogenic tumor of the oral cavity and accounts for about 1 percent of all oral tumors and 11% of all odontogenic tumors. Ameloblastomas are present over a wide age range, but rarely seen in children [3]. Most cases are diagnosed during the third and fifth decades of life. About 80% of ameloblastomas occur in the mandible with 70% arise in the molar region and ascending ramus, 20% in the premolar region, 10% in the incisor region and about 20% occur in the maxilla, mostly in the molar region and can extend to involve the maxillary antrum too [3]. According to the World Health Organization classification in 2005 ameloblastoma has been classified into four types: multicystic or conventional solid, unicystic, peripheral, and desmoplastic. The most common type is multicystic and it accounts for about 75-86% of all cases [4]. Histologically ameloblastoma can have plexiform or follicular patterns, and these patterns are described according to the arrangement of the tumor epithelium [2]. In some tumors, both patterns coexist [3].
Radiographically, ameloblastoma can appear as multilocular or unilocular radiolucency, most commonly it appears as a multiloculated radiolucency resulting in a honeycomb or as a soap bubble * Corresponding author. appearance. Roots of the teeth involved in the lesion may show varying degrees of resorption [4].
The tumor is slow-growing and in its earliest stages, it might be asymptomatic and could be discovered incidentally. But when the tumor enlarges patients start to have symptoms like pain, facial deformity, and enlargement of the jaw-bones [4].
This case report presents a case of a rare unicystic maxillary ameloblastoma in a 3.5-years old child. All work has been reported in line with the SCARE criteria [1].

Case presentation
A 3.5-year old girl, with no medical history, presented with swelling and pain on the left side of the face. Initially, two months back the swelling was asymptomatic, it was smaller in size, but it gradually enlarged to the present size and extended to the floor of the orbit, causing facial deformity and pain (Fig. 1). There was no history of trauma or discharge reported by the parents. The patient had pressure symptoms from the enlarged swelling.
On extraoral examination, a diffused swelling over the left side of the face measures about 7 × 7 cm, involving the maxilla and the left eye. The skin overlying the swelling was stretched, the surface was smooth, and the skin color was normal. In palpation, it was hard and painful with no local rise in temperature. Intraoral examination revealed diffuse swelling in the left maxilla, extending from the midline to the posterior molars area and expanding laterally to involve the buccal vestibule and the cheek (     0.8 × 0.6 × 0.5 cm removed from the swelling and sent to an oral pathologist for histopathological examination. The microscopic examination of the multiple serial sections prepared from the specimen revealed strips of stratified squamous epithelium and underlying tumor tissue formed of odontogenic epithelial islands composed of non-keratinized stratified epithelium of 2-4 layers devoid of superficial keratinization with no rete ridges and with a flat interface formed by peripheral palisading of columnar cells at the basal layer with hyper-chromatic nuclei, the cells show reverse polarization away from the basement membrane with stellate reticulum-like cells, suprabasal cells composed of loosely arranged angular cells. These findings were strongly suggestive of unicystic ameloblastoma. As the lesion was very extensive, the entire tumor has been removed using an extraoral incision (Weber Ferguson) (Figs. 8 and 9) [5], After tumor exposure lesion appeared to be extending from midline till pterygoid plates on the left side and superiorly to the floor of the orbit. partial maxillectomy performed  with removal of the floor of orbit with 1 cm safety margins from all directions using surgical saw and osteotomes. immediate reconstruction using the buccal pad of fat (Figs. 10 and 11) [5] was done. The specimen was sent to the histopathology department and all margins were safe. The patient was followed up for one year and showed excellent healing and good functional and esthetic outcome. (Fig. 12) only 3 mm fistula remains in the palate which will be addressed later in a simple operation with no evidence of complication or recurrence.

Discussion
Ameloblastoma is a locally aggressive, epithelial odontogenic neoplasm, histologically, it resembles an enamel organ. It is non inductive which means that it fails to induce any formed calcified product such as enamel, dentin, or other materials [7].
Ameloblastoma is classified into four types: multicystic, unicystic, peripheral, and desmoplastic. The most common form is the multicystic one. This case report discusses the unicystic type. The unicystic ameloblastoma was originally described by Robinson and Martinez in 1977. Unicystic ameloblastoma in comparison to multicystic ameloblastoma occurs mostly at a younger age with a range of 10.6-23.8 years [7]. The average age of the patient at the time of initial diagnosis was 32.5 years, which is similar to that in the Chinese population in whom tumors were presented at the mean age of 32.4 years. Overall, it may be said that it is a disease involving the middle-age population in most cases [9].
If a preliminary diagnosis of ameloblastoma is made, then CT imaging is highly recommended. CT imagining can demonstrate the anatomical extent of the tumor, therefore it can detect perforation of the outer cortex and invasion into surrounding soft tissues. Accordingly, if the soft tissue invasion is extensive then   Fig. 12. One year follow up with remaining 3 mm fistula in the palate which will be addressed later.
Magnetic Resonance Imaging (MRI) is recommended. In a postsurgical follow-up, CT examination is crucial [8].
Incisional biopsies of large jaw cysts should be carefully examined for the presence of ameloblastomatous change, the enucleated specimens should be thoroughly sectioned to rule out mural or transmural extension. Unicystic ameloblastoma mostly is found as luminal and intraluminal forms [2].
For Cystic ameloblastoma, treatment options can range from enucleation to resection, although they are more likely to recur if enucleated [2]. In our case the lesion was very extensive, the entire maxilla with the tumor has to be removed using Weber Ferguson flap, along with reconstruction using the buccal pad of fat. The result was acceptable with one year follow up. In general, ameloblastoma should be followed indefinitely because of recurrences may be seen as long as 10-20 years after primary therapy. Ameloblastomas of the maxilla generally are more difficult to treat and manage than those of the mandible because of the anatomic relationships. In addition, the maxilla contains more cancellous bone than the mandible. Therefore, intraosseous maxillary ameloblastomas are often excised with a wider normal margin than the mandibular tumors [6].

Conclusion
This case of Unicystic Ameloblastoma was diagnosed carefully based on history and investigations. Ameloblastoma is more common in the mandible than in the maxilla, and in middle age than in children. Very rarely, we come across a case of ameloblastoma in the maxilla in a 3.5 years old child. Unicystic ameloblastoma is a tumor with a strong propensity for recurrence. Therefore, Adequate maxillectomy was performed with simultaneous reconstruction using buccal pad of fat with very acceptable results both functionally and esthetically.

Declaration of Competing Interest
We wish to confirm that there are no known conflicts of interest associated with this publication and there has been no significant financial support for this work that could have influenced its outcome.

Funding
No funding was received for this work.

Ethical approval
In accordance to declaration of Helsinki Patient guardians wrote informed consent for surgical intervention and for publication.

Consent
"Written informed consent was obtained from the patient guardians for publication of this case report and accompanying images. A copy of the written consent is available for review by the Editor-in-Chief of this journal on request".

Provenance and peer review
Not commissioned, externally peer-reviewed.