International Journal of Head and Neck Sciencea 1(4) 2017 251

International Journal of Head and Neck Science 1(4): 251-257, 2017DOI: 10.6696/IJHNS.2017.0104.07Case Report

Ameloblastoma: Hemimandibulectomy and Reconstruction with Free Fibular Graft— A Case Report and Review of the Literature

Marlinda Adham1,3, Zanil Musa1,3, Parintosa Atmodiwirjo2,3, Kristaninta Bangun2,3, Eriza1,3

1 Department of Otorhinolaryngology—Head & Neck Surgery, Dr. Cipto Mangunkusumo National Central General Hospital, Jakarta, Indonesia

2 Department of Plastic Surgery, Dr. Cipto Mangunkusumo National Central General Hospital, Jakarta, Indonesia3 Faculty of Medicine, University of Indonesia, Jakarta, Indonesia

Background: Ameloblastoma is a benign odontogenic tumor which arises from dental epithelium. It tends to be slow growing and is usually asymptomatic. The areas of predilection are where teeth develop, e.g., mandible (80%) and maxilla (20%). The diagnosis is achieved by biopsy. Successful management of ameloblastoma is based upon complete tumor removal which may result in facial asymmetry and a defect that requires facial reconstruction.Methods: We report a case of a massive ameloblastoma of the right mandible and maxilla.Results: Tumor removal required a hemimandibulectomy. The defect was reconstructed with a free vascularized fibular graft. The surgical team included an otorhinolaryngologist who removed the tumor and plastic surgery colleagues who did the reconstruction with a free fibular graft.Conclusions: The most important aspect of treatment of ameloblastoma is complete removal of the tumor in order to prevent recurrence. The challenge of managing a large ameloblastoma is not only the complete removal of the tumor, but also considering the best technique for reconstruction of the mandible, filling the defect, and restoring function and cosmetics.

Key words: benign odontogenic tumor, ameloblastoma, mandible, mandibular reconstruction, free fibular flap

Received: June 16, 2017; Accepted: August 1, 2017.Corresponding author: Marlinda Adham, MD, Department of Otorhinolaryngology―Head & Neck Surgery, Dr. Cipto Mangunkusumo National Central General Hospital, Jalan Pangeran Diponegoro No. 71, Salemba, Senen, RW. 5, Kenari, Senen, Kota Jakarta Pusat, Daerah Khusus Ibukota Jakarta 10430, Indonesia. Tel: 62-21-3910701, E-mail: marlinda.adham@yahoo.com

Introduction Case ReportAmeloblastoma of the mandible is a benign

odontogenic tumor developing from the components of the enamel organ (epithelial rests of Malassez), re-ported by Falkson in 1987.1

These tumors are slow growing, but may be-come large enough to cause deformity. Inadequate surgery is accompanied by a high recurrence rate. Histopathologically, the most common types of ame-loblastoma are follicular and plexiform. Other types of ameloblastoma include achantomatous, granular

and basal cell. Ameloblastoma can affect all ages, but is mainly found in the 20–50 years old range, with an average age of 27 years. The incidence of amelo-blastoma is similar between males and females. The majority of these tumors arise in the mandible (80%); most frequently in the posterior region of the mandi-ble. In the maxilla, 20% of the ameloblastoma is fre-quently found in the maxillary tuberosity.

The management of ameloblastoma is surgical. The use of the curettage technique has a high re-currence rate and is therefore discouraged. The best

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chance for cure requires wide resection with approx-imately 1 cm margins with immediate reconstruction of the mandible. The most commonly used reconstruc-tion technique is vascularized osteocutaneous free flap with plate-screw mandibular reconstruction. The fibula is the primary source of bone for reconstruction of almost the entire segment of the mandibular defect since it has a very good quality of blood vessels. We report a case of massive ameloblastoma of the right mandible and review of the literatures regarding the choice of mandibular reconstruction techniques.

Case A 34-year-old male presented to our clinic

with an eight years history of a gradually expanding painless mass in the right face. The patient could eat and drink normally. Physical examination revealed a solitary mass in the right mandibular region measur-ing 25 cm × 13 cm × 10 cm, causing marked facial asymmetry. The mass was cystic to touch and fixed (Fig. 1). The edge of the mass was hyperemic, tender, and partially necrotic. There were nopalpable lymph nodes in the neck. There was no trismus, good oral

hygiene, and the buccal mucosa was intact. Biopsy of the mass had been done 8 years ago with a diagnosis of ameloblastoma.

The computed tomography (CT) of the mandible with and without contrast (Fig. 2) demonstrated an inhomogeneous multicysticmass, measuring 12.34 cm × 12.95 cm with calcifications. Three dimensional CT also demonstrated destruction of right mandible and maxilla (Fig. 3). The zygoma was intact.

The planned surgery included extirpation of the mass, hemimandibulectomy through a lip splitting in-cision and reconstruction of the mandible with a free vascularized fibular graft. The lip splitting incision was done at the level of the right second incisor. The tumor mass involved the body of the mandible, the coronoid process and part of the condyle. The angle of the mandible could not be identified. Superiorly, at the attachment to the zygoma, the tumor mass was released from the surrounding tissue. There was a cyst in the floor of the mouth attached to the mylohyoid muscle and right mandible. A right hemimandibulec-tomy was carried out along with the removal of the cystic tumor (Fig. 4). The mass was extirpated com-pletely and measured 14 cm × 10 cm × 5 cm in size

Fig. 1. The photo revealed a solitary mass, measuring 25 cm × 13 cm × 10 cm, involving the right mandible, maxilla and buccal space.

Fig. 2. Coronal computed tomography (CT)-scan revealed a multicystic tumor of the mandible with bone destruction in the right maxillary and mandibular region.

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and consisted of cystic and solid components (Fig. 5). Histopathology showed a plexiform and follicular type of ameloblastoma (Fig. 6).

Harvesting of the free fibular flap was carried out simultaneously with tumor resection. The perfo-rator artery was found through the use of the Doppler. The image design was then made. The anterior ap-proach incision was made through the skin and subcu-taneous tissue. The septal perforator was traced until the fibula was identified. The muscle was set aside until the intraosseous septum was identified. An os-teotomy was carried out at the distal boundary of the fibula (6 cm from the lateral malleolus) and the proxi-mal boundary (4 cm from the head of the fibula). The fibula was clamped in the proximal and distal end and then rotated, until the peroneal artery was identified. The fibular graft was released from the surrounding muscle and the muscle sutured. The skin was sutured

Fig. 3. Three-dimensional computed tomography (CT) demonstrated destruction of the right mandible and maxilla.

Fig. 4. Photo of the surgical specimen was shown. The arrow showed the floor of the mouth. The cyst wall was attached to mylohyoid muscle and mandibular region.

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over a suction drain. The facial artery and jugular vein were identified. The mandibular defect was 11 cm long. The design for molding the fibula was created in accordance with the drawings. Fibular reconstruction was done with plate-screw design with a double bar-rel (Fig. 7). The fibular graft was then fixed to the na-tive mandible with plate and screws. The anastomosis was performed end to end artery between facial artery with peroneal artery and to end vein of the jugular vein branches. The gingivobuccal mucosa was sewn to the floor of the mouth covering the mandible and the fibula, with water tight technique. The muscles were sutured and the skin was closed over and a suc-tion drain was left.

Postoperatively, the patient was immobilized and fed through a nasogastric tube. The extra-oral surgical wound was dry and there were no signs of infection. Intra-orally there was neither purulent ex-udate nor bone exposure. The patient was mobilized for one week postoperatively, and there were no signs of wound infection. Results of scheduled anterolater-al radiograph shown that the bone graft appeared to be misaligned so the patient underwent a revision of the fibular graft. During the operation, the fibula and zygoma were drilled and a 0.4 mm wire was placed. 8 mm sized internal maxillary fixation put on and occlusion was achieved. Intraorally there was bone expose, but there are no signs of infection.

The patient had no complaints on his first visit to the outpatient clinic 3 weeks postoperatively. He had begun his usual activities, eating and drinking, mostly chewing on the left side. There was significant improvement in the facial deformity (Fig. 8). The sur-gical wound in the mandibular region was dry and the wound edges were not hyperemic; besides, there was no purulent exudate. However, there was mandibular bone exposed on the right side of the incision near the lip area (Fig. 9). The patient subsequently underwent

Fig. 6. Photomicrograph demonstrated follicular and plexiform type of ameloblastoma.

Fig. 7. Mandible reconstruction was done with free vascularized fibular graft with double barrel technique.

Fig. 5. Surgical specimen demonstrated a mass measuring 14 cm × 10 cm × 5 cm with solid and cystic components.

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revision to cover the exposed bone. The Division of Prosthodontics in Dr. Cipto Mangunkusumo National Central General Hospital was consulted for an intra-oral prostheses.

DiscussionAmeloblastoma of the mandible can grow to

massive size and cause facial asymmetry. In this case, the patient presented with complaints of a mass which grew on the lower right cheek and jaw causing facial asymmetry. According to the literatures, the amelo-blastoma is initially asymptomatic, characterized by a mass in the mandible causing facial asymmetry. Ameloblastoma can affect all ages, but is usually found in the age range of 20–50 years. The incidence of ameloblastoma is equal between men and women. According to the literature, the tumor is found 84% in the mandible and 16% in the maxilla.2-5

CT imaging was done revealing a tumor of the right mandible with inhomogeneous density, domi-nated by a cystic component with destruction of the right mandible and maxilla. Computer tomography is helpful in identifying the expansion of the tumor into surrounding tissues in the oral cavity, infratemporal fossa and submandibular region.6

Postoperative histopathologic examination re-vealed aplexiform and follicular type of ameloblas-toma. These histopathological types are reported to have a low recurrence rate.7

The objective of management of the tumors is through wide excision and tumor free margins. The objective of reconstruction is to restore the mandib-ular arch and to return the function of the mandible such as mastication, deglutition, speech and mouth movement. Reconstruction also has a role in airway management by supporting the tongue muscles. Re-construction of the mandible also improves the cos-metic appearance of the face.8

Nakamura reported that in 78 cases of amelo-blastoma, there was a 33% recurrence rate after con-servative treatment and a recurrence rate of 7.1% after radical surgery. The best treatment for ameloblastoma appears to be wide excision of the mass.9 Conserva-tive management influences high rate of recurrences. Sehdev10 reported a local recurrence rate of 90% in patients with ameloblastoma that was treated only with curettage.

Management of this patient included tumor ex-tirpation and right hemimandibulectomy, which was expected to minimize the possibility of recurrence. This is consistent with the experience in a previous literature.9

Radiation is rarely used as primary treatment for ameloblastoma. However, radiation therapy is

Fig. 8. Post-operative photo demonstrated significant improvement of the facial deformity.

Fig. 9. The arrow pointed to the exposed bone after reconstruction with free vascularized fibular graft.

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commonly used in cases which cannot be treated with surgery or in patients with large tumors who have already undergone repeated surgery. This is based on the fact that ameloblastoma is an epithelial tumor that is radioresistant.9,11

The reconstruction technique chosen in this case was the vascularized free fibular graft. The fibula is the primary choice for reconstruction of almost the entire mandibular defect, with a very good quality of blood vessels, and up to 27 cm of bone stock. Dis-section is simultaneous with resection of tumor in the mandible, which is time efficient and results in low morbidity at the donor area.8

Reconstruction techniques, which may be used, include vascularized osteocutaneous flaps, and recon-struction plates with and without soft tissue pedicled flaps.8 Reconstruction can be done with and without soft-tissue pedicle flaps, such as stainless steel or ti-tanium plates. These plates have a very high success rate if used for reconstruction in short lateral segment-ed defects.8

Reconstruction in cases of a major defect is a challenge for the head and neck surgeon. Various ma-terials can be used for reconstruction such as aloplas-tic implants autogeneous bone graft, allogenous bone graft, pedicle composite bone flaps, free tissue trans-fer of vascularized bone flaps. Other materials for implants that can be used include are pins, trays and plates, silicone polymerase, polyurethane-reinforced dacron polyester mesh stainless steel. The common-ly used bone graft is autogeneous bone graft which consists of corticanceous blocks, cancellous bone, cortical bone and the particular combination with can-cellous bone marrow.8

Beside osteocutaneus vascularized bone graft, several reconstruction techniques common used for reconstruction of the mandible are the nonvascular-ized bone grafts, and plate reconstruction with/without soft tissue pedicle flaps.8 The use of nonvascularized bone grafts has a success rate of 17–20%; therefore it is indicated for small size partial or segmental defects of the mandible.8

Some institutions also use stainless steel or ti-tanium plates for reconstruction. These plates have a high success rate when used for reconstruction of the lateral segment of a short defect. The risk of plate extrusion increases when soft tissue or mucosa is re-sected, or if the plate is placed anteriorly. Mandibular reconstruction with plates is only indicated for the

short lateral segments, patients who did not undergo resection of soft tissue or mucosa, and patients that will not undergo radiation.8,11

Free flap failure is the single most important complication associated with the head and neck area. Fortunately, most compromised flaps can be salvaged, and the actual incidence of total flap loss is generally less than 5%. Reconstruction plate or bone exposure and intraoral wound dehiscence constitute other po-tentially serious problems. Donor site complications are uncommon and rarely require additional surgery. Delayed skin graft healing (fibula), pain, foot instabil-ity and fractures can occur.11,12

The most important aspect of treatment of ame-loblastoma is complete removal of the tumor in order to prevent recurrence. The challenge of managing a large ameloblastoma is not only the complete removal of the tumor, but also considering the best technique for reconstruction of the mandible, filling the defect, and restoring function and cosmetics.

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9. Nakamura N, Higuchi Y, Mitsuyasu T, Sandra F, Ohishi M. Comparison of Long-Term Results Between Different Approaches to Ameloblastoma. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2002;93:13-20.

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Mandible. Cancer 1974;33:324-333. 11. Disa JJ, Hidalgo DA. Mandible reconstruction. In: Thorne

CH, Beasley RW, Aston SJ, Bartlett SP, Gurtner GC, Spear SL, editors. Grabb and Smith’s Plastic Surgery. Philadel-phia, PA: Wolter Kluwer; 2007. p 428-437.

12. Pieptu D, Gogalniceanu D, Getu N, Grosu O, Popescu S, Costan V. Mandible Reconstruction Using the Free Os-teocutaneous Fibula Flap. Timisoara Med J 2005;55:43-48.