Surgical management of mandibular ameloblastoma and immediate reconstruction with iliac crest and costochondrial bone grafts: A case report

Abstract

Introduction and importance

Ameloblastoma is a benign but locally aggressive odontogenic tumor mostly occurring in the jaws. Ameloblastoma can be difficult to diagnose because it mimics other benign lesions. Its diagnosis requires a combination of imaging data, histopathological analysis, and molecular tests. Its treatment modality diverges from simple enucleation with bone curettage up to wide surgical resections.

Case presentation

A 25-year-old female presented with a right-sided mandibular mass for five years. Histopathology and radiology tests confirmed it to be an ameloblastoma. A hemimandibulectomy was done, followed by immediate reconstruction using an autogenously inserted iliac crest bone and a costochondral graft as an interposition graft for the lost part. The patient had a satisfactory clinical outcome, and no sign of recurrence after a follow-up of six months.

Clinical discussion

The ideal management of ameloblastoma should minimize recurrence, restore function and appearance, and present minimal donor site morbidity. While the removal of a wide part of the bone and soft tissue leads to defects that may cause functional and aesthetic concerns, conservative management is associated with minimal downtime but high recurrence rates. Reconstructive surgery is of paramount importance for the recovery of the lost parts in these patients.

Conclusion

Radical surgery is the treatment of choice for large tumors to minimize recurrence, and immediate reconstruction utilizing grafting techniques is essential to restoring function and appearance. The autologous bone graft technique is satisfactory for immediate mandibular reconstruction as it represents a simple, easy, less costly, and reliable method for restoring mandibular continuity defects.

Highlights

• •Slow-growing, locally aggressive odontogenic epithelial neoplasm.
• •Most commonly, occurs in the mandible.
• •Large tumor treatment involves surgical resections to minimize recurrence.
• •Reconstructive surgery is key to restoring function and aesthetics.
• •The autologous bone graft technique is a simple, cost-effective, and reliable method for restoring mandibular continuity defects.

1. Introduction

Ameloblastoma is the most common benign odontogenic tumor of epithelial origin that exhibits locally aggressive behavior with a high rate of recurrence [1,2]. It is believed theoretically to originate from the dormant dental lamina, the enamel organ in development, the epithelial lining of odontogenic cysts, or from the cells of the basal layer of the oral mucosa. Ameloblastoma accounts for 1 % of all oral cavity tumors, with 90 % of these located in the mandibular region [3]. It is a slow-growing but locally invasive tumor that appears as a painless swelling of the mandible or maxilla with buccal and lingual expansion. It commonly affects the mandibular posterior region and has a high possibility of causing tooth mobility, displacement, and root resorption. Clinically, it is classified into multicystic (solid), unicystic, peripheral, and malignant subtypes. It appears unilocular or multilocular in radiographic images and is described as a soap bubble or honeycomb [4,5]. This tumor is reported to be relatively rare in young adults and accounts for about 10–15 % of all documented cases of ameloblastoma of jaw bones [3,4].

Surgical management is the mainstay of the treatment of ameloblastomas. The management protocol for ameloblastoma depends on the extent of involvement, anatomical location, histologic type of the ameloblastoma, and the size of the tumor [6]. Treatment of ameloblastoma may vary from a simple enucleation to segmental or en-block resection of the tumor with reconstruction [7]. To prevent recurrence, the surgical margins should be at least 1–2 cm of radiologically normal margins. On the other hand, there is a school advocating more conservative surgical management by enucleation with adjacent bone [8]. However, this approach has shown a significant recurrence rate for the tumor. This work has been reported in line with the SCARE 2023 criteria [9].

2. Case presentation

A 25-year-old female patient reported to the department of dental surgery at the oral and maxillofacial unit at our institution with a chief complaint of a right-sided mass on the face for about 5 years (Fig. 1A). The mass had a gradual onset and was progressively increasing in size, with no aggravating or relieving factors. However, it was associated with on-and-off pain and difficulty chewing on the right side of the jaw. The patient had no history of fever or weight loss. The general and systemic examinations were normal. On local examination, she had facial asymmetry due to a mass on the right side of her face measuring about 10 cm by 6 cm in its greatest dimension. She was able to open the mouth fully, with no laceration visible. The mass extended from the zygomatic arch to the submandibular region superior inferior. It was firm and non-tender on palpation. Intraorally, the mass was visible almost from the parasymphisis menti to the retromolar pad posteriorly. The expansion of both the lingual and buccal cortical plates was clinically visible. All of the involved teeth were mobile.

Fig. 1.

Photographs of the patient before surgery demonstrating mandibular mass on the right side causing facial asymmetry (A); appearance of the patient 10 days post hemimandibulectomy surgery and jaw reconstruction (B&C); and six months after the surgery and jaw reconstruction (D–F), respectively.

A clinical impression of ameloblastoma with differential diagnoses of odontogenic fibroma and adenomatoid odontogenic tumor was entertained. The orthopantomograph (OPG) showed a multilocular radiolucency appearance on the right side of the lower jaw (Fig. 2A). A biopsy was performed, and the histological results highlighted islands of epithelial cells with central edema and loose arrangement, bordered by a rim of palisading columnar cells. In some areas, there were also aggregates of eosinophilic granular cells (Fig. 3A-B). The pathologist concluded the diagnosis of granular cell ameloblastoma. Informed consent was sought from the patient, and when it was obtained, the surgical procedure was scheduled.

Fig. 2.

Orthopantomography x-ray of the patient demonstrating a multilocular lesion on the right side of the mandible extending from the mental foramen to the condylar neck causing displacement of teeth (blue arrows) (A), the control radiography six months after surgery (B). (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)

Fig. 3.

Photomicroscopic images of the lesion showing islands of epithelial cells with central edema and loose arrangement, bordered by a rim of palisading columnar cells. The morphology is consistent with ameloblastoma; H&E staining at 40× original magnification (A) and high magnification at 200× original magnification (B).

3. Surgical procedure

The patient was planned for surgery under general anesthesia. The patient was intubated through an endotracheal tube via the left nostril. The mucosa and skin around the lesion were marked and incised (Fig. 4A). A hemimandibulectomy was performed, including 2 cm from the radiographic margin. The surgery was performed by a team of experts' oral and maxillofacial surgeons. The whole tumor mass was excised along with the mucoperiosteum and overlying mucosa (Fig. 4B). Immediate reconstruction of the defect with a vascularized free fibular flap (FFF) was considered; however, due to the patient's previous history of trauma and surgery, rib and anterior iliac crest bone tissues were harvested from the left side of the body (Fig. 4C). A titanium metal plate was manually bent to make the shape of the mandible (Fig. 4D). At that point, the bone fragments were arranged on the metal plate, with the cartilaginous part of the rib bone shaped to fit in the glenoid fossa, while the bony part of the rib was used for reconstruction of the ascending ramus of the mandible (Fig. 4E). The iliac crest bone was used for reconstruction of the body and the angle of the mandible. The surgical wound (Fig. 4F) was primarily closed with advancement of adjacent mucosa after layer-to-layer closure in a water-tight fashion by vicryl suture. The patient was given antibiotics and analgesia.

Fig. 4.

Photographs of the patient demonstrating surgical exposure of the tumor intraorally during surgery (A); a resected tumor in a hemimandibulectomy surgical specimen (B); harvested rib and anterior iliac crest bone tissues, and a titanium metal plate (C); a manually bent titanium metal plate simulating the patient's mandible (D); the bone fragments arranged on the metal plate with the cartilaginous part of the rib bone shaped to fit in the glenoid fossa, while the bony part of the rib was used for reconstruction of the ascending ramus of the mandible (E); and the surgical wound closure with advancement of adjacent tissue in a water-tight fashion by vicryl suture (F), respectively.

4. Outcome and follow-up

The patient had a satisfactory clinical outcome (Fig. 1B, C) with no post-operative complications and no sign of recurrence (Fig. 1D, E, and F). Control OPG radiography was done after six months (Fig. 2B). The patient had no tumor recurrence during postoperative follow-up after 2 years.

5. Discussion

Ameloblastoma is an aggressive, benign, slow growing odontogenic epithelial tumor. It accounts for about 1 % of all tumors and cysts of the jaw bone [4]. It is the most clinically important odontogenic tumor. Although ameloblastomas occur with equivalent frequency in both genders, they are found to occur slightly more frequently in women than men, as is seen in this case [10]. As it was in our patient, the reported cases of ameloblastoma are 20–50 years of age. Despite having benign clinical behavior, ameloblastoma can rarely metastasize (metastasizing ameloblastoma). Metastasizing ameloblastomas usually metastasize to lymph nodes or the lung; other sites are possible with organ-associated symptoms. This behavior is associated with longstanding tumors, multiple surgical procedures, and radiation therapy. It is documented that ameloblastoma tends to recur in 10, 20, or even 30 years after the initial operation [5]. The majority of ameloblastomas of the mandible are located in the molar ramus region, and most of them are found in association with an unerupted tooth [5]. This is similar to our patient, where the lesion was located on the body of the ramus.

Clinically, ameloblastoma occurs as an asymptomatic mass, increasing in size slowly with expansive bone destruction [5,10]. This is why the majority of patients do not report to the hospital to seek early intervention. The same phenomenon was mirrored in our case, in which the lesion has been there for five years. Ameloblastoma can be associated with facial asymmetry due to mass, dental impaction, tooth displacement, tooth mobility, root resorption, root divergence, and occlusal interference. This is similar to our patient, who presented with facial asymmetry due to a lesion from the body to the ramus of the mandible, which stayed there for more than five years. Similarly, our case presented with multilocular lesions with root resorption radiologically.

Treatment modality for ameloblastoma ranges from simple enucleation up to wide surgical resections [6]. This depends on the anatomical location and size of the lesion. Removal of a wide part of the bone and soft tissue leads to defects that cause functional and aesthetic concerns. Therefore, reconstructive surgery is of paramount importance for the recovery of the lost tissue in these patients [8]. Complete surgical removal of the lesion, including the extension of a safe margin with at least 1 cm to 2 cm thickness to reduce the risk of recurrence of the tumor, and restoration of function and appearance are the main goals of treatment. A tumor excision is ideally followed by reconstruction with a bone graft or flap and dental prostheses [10,11]. Reconstruction is easier if done earlier due to a lack of scarring or contracture, and it can be advantageous psychologically [12]. In our case, the lesion was very large, so the treatment was hemimandibulectomy followed by immediate reconstruction using a costochondrial graft and anterior iliac crest bone. Grafted bones were supported with a titanium reconstruction metal plate, followed by a tooth prosthesis later. Long-term, periodic follow-up is recommended even after successful treatment of ameloblastoma due to the potential for delayed presentation of recurrent disease. All patients treated should be followed clinically and radiographically by periapical and panoramic x-rays. In our patient, periodic follow-up examinations were performed every six months for two years with no complications observed. Recurrent ameloblastoma may be difficult to treat [6]. Currently, targeted therapies and novel nonsurgical therapeutics are being explored for the management of non-resectable tumors, with the aim of avoiding surgery or minimizing surgical scope. For instance, MEK and BRAF inhibitors have been observed to decrease tumor size, slow down tumor progression, and reduce bone pain [13,14].

6. Conclusion

Ameloblastoma is a rare, benign, but locally invasive odontogenic jaw tumor with a high recurrence rate. Radical surgery and immediate reconstruction are the treatments of choice due to the large size of the lesion. The autologous bone graft technique is satisfactory for immediate mandibular reconstruction as it represents a simple, easy, less costly, and reliable method for restoring mandibular continuity defects. Long-term follow-up and radiography examinations are essential.

Informed consent

Written informed consent was obtained from the patient to publish this case report and accompanying images. On request, a copy of the written consent is available for review by the Editor-in-Chief of this journal.

Ethical approval

A waiver for ethical approval was obtained from the Clinical Research Ethics Committee (CREC) at author's institution because individual case studies or case series do not require ethics committee approval. The surgical procedure was conducted in accordance with the principles of the Declaration of Helsinki.

Funding

This work did not receive any funding from any source.

Author contribution

Kanankira A Nnko: Conceptualization; data curation; writing –original draft.

Raphael T Pima: Data curation; writing –original draft.

Calvin Baraka: Data curation; writing –review and editing.

Enock A. Robi: Data curation; writing –review and editing.

Deogratius S. Rwakatema: Data curation; supervision, writing –review and editing.

Alex Mremi: Conceptualization; investigation; methodology, writing –original draft; writing – review and editing.

Guarantor

Alex Mremi.

Research registration number

• 1.Name of the registry: Not applicable.
• 2.Unique identifying number or registration ID: Not applicable.
• 3.Hyperlink to your specific registration (must be publicly accessible and will be checked): Not applicable.

Conflict of interest statement

All authors have declared that no competing interests exist.

Data availability

There is no data generated from this study.