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Indian J Dent Adv 2012; 4(2) 843

Unicystic Ameloblastoma: A Diagnostic

Dilemma and Its Management Using FreeFibula Graft: An Unusual Case Report

Aniket J ain1, Satyajit Dandagi2, Amit Sangle3, Viquar Ahmed4, Akram Khan5

ABSTRACT:

A 20 year old patient reported with a swell ing in the left posterior

mandibular region since 4 months. On clinical examination,

there was a hard, non-tender mass, measuring 8.5 cm by 5 cm

arising from the left side of the mandible, involving the ramus,

angle and body upto the leftt lower 1st premolar tooth.

Radiographic picture and fluid aspiration of the pathology with

protein analysis of 4.1 gm/dl, was suggestive of a keratinizing

cyst or tumor. Hemimandibulectomy was performed with safe

margins and an microvascular free fibula graft was placed for

mandibular reconstruction. The final diagnosis after

histopathological examinati on was given as Unicysti c

Ameloblastoma. Facial Symmetry is well maintained with no

recurrence after a systematic follow up of 18 months.

Key words: Unicystic Ameloblastoma, Microvascular, Free

Fibula Flap

C A S E R E P O R T

doi: ...........................

1Final Year P.G Student2Professor3Professor4Senior Lecturer5First year P.G. Student

Department and I nstitution Dept of Oral andMaxillofacial Surgery, M A Rangoonwala College ofDental Sciences and Research Centre, Pune.

Article Info:

Received: April 15, 2012;Review Completed: May, 14, 2012;Accepted: J une 13, 2012Published Online: August, 2012 (www. nacd. in)NAD, 2012 - All rights reserved

Email for correspondence: draniketjain@gmail .com

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INTRODUCTION:

The most common tumour of odontogenic origin is ameloblastoma, which develops from epithelial cellular

elements and dental tissues in their various phases of development. I t is a slow-growing, persistent, and

locally aggressive neoplasm of epithelial origin.1 Unicystic ameloblastoma is second important clinical type

of ameloblastoma and accounts for 10-15% of all intraosseous ameloblastomas.2They have been reported to

occur in second and third decades of life as against its solid counterpart which occurs in fourth decade of life.

Unicystic ameloblastoma most commonly occurs in posterior mandible followed by parasymphysis region,

anterior maxilla and posterior maxilla.3 It is a classic example of a true neoplasm of enamel organ type

tissue that lacks the potential to undergo differentiation, and hence has aptly been defined as unicentric,

nonfunctional, intermittent in growth, anatomically benign and clinically persistent by Robinson.There are

three forms of ameloblastomas, namely multicystic, peripheral, and unicystic tumors [4]. Multicysticameloblastoma is the most common variety and represents 86% of cases. Peripheral tumors are odontogenic

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tumors, with the histological characteristics of

intraosseous ameloblastoma that occur solely in the

soft tissues covering the tooth-bearing parts of the

jaws. Unicystic tumors include those that have beenvariously referred to as mural ameloblastomas,

luminal ameloblastomas, and ameloblastomas

arising in dentigerous cysts [5]. I t refers to those

cystic lesions that show clinical, radiographic or

gross features of jaw cyst, but on histologic

examination shows typical ameloblastomatous

epithelium, lining part of the cystic cavity with or

without luminal and/or mural tumor growth.6 We

present a case of a large unicystic mandibular

ameloblastoma in a young male.

Case Report:

A 20-year-old female presented to Department

of Oral and Maxillofacial Surgery with the Chiefcomplaint of painless swell ing in left side of the face

since 4 months which was gradually increasing in

size. Patient was apparently alright 4 months back,

suddenly developed a small swelling in lower left

mandibular region which gradually increased in size

to attain the present state.(Fig 1) There was no

associated pain, difficulty in opening the mouth,

chewing or articulating. On physical examination,

there was a hard, non-tender mass, measuring 8.5

cm by 5 cm arising from the left side of the mandible,

involving the ramus, angle and body upto the leftt

lower 1st premolar tooth. Diffuse overgrowth seen

in lower left posterior alveolar and vestibular region

with normal overlying mucosa(Fig. 2). No neck

nodes were palpable. Systemic examination was

normal. An Orthopantomogram (OPG) was done,

which showed large cystic lesion in the left side of

mandible extending from lower left second premolar

upto the ramus involving the condyle as well.

Radiographic examination revealed a unilocular

appearance and was suggestive of a cyst or tumour.

(Fig 3 and 4) An aspirate of the fluid was obtained,

and protein analysis revealed 4.1 gm/dl, which was

suggestive of a keratinizing cyst or tumor. F ine

needle aspiration cytology of the lesion as well as

incisional biopsy was performed but both were not

conclusive.Patient was taken up for surgery undergeneral anesthesia. Exposure of the lesion was done

via extended risdons incision followed by

hemimandibulectomy along with dearticuation of

the TM joint on the left side (F ig. 5 and 6).

Reconstruction was done using a microvascular free

fibula graft. Shaping of the resected fibula was done

according to the preoperative template. A miniplate

with locking screws was used to secure theosteotomized fibula and the mandible (Fig. 7 and

8). Final diagnosis of unicystic ameloblastoma was

confirmed with the help of histopathologic

examination of the excised specimen (F ig. 9). Facial

symmetry was well maintained postoperatively. One

year systematic follow-up did not reveal any

recurrence as well as showed excellent acceptance

of graft in the region mimicking a lower jaw. (Fig

10 and 11)

Discussion:

Robinson and Martinez were the first persons

to describe UA in 1977.7,8 I t is most commonly seen

in individuals who are 16 to 20 years of age.Occasionally, lesions occur in younger patients;

rarely, they have been found in patients up to the

age of 40.9 About 90% of the lesions are located in

the mandible and between 50 to 80% of these cases

are associated with an impacted tooth.10,11 As seen

in the present case, the unusual aspect is that its

not associated with an imapacted tooth. Facial

asymmetry due to swell ing is the regular presenting

feature which infrequently relates with pain.

Unilocular ameloblastoma (UA) is a rare type

of ameloblastoma, accounting for about 6% of

ameloblastomas.It refers to those cystic lesions that

show clinical, radiographic or gross features of a

mandibular cyst, but on histologic examination

shows a typical ameloblastomatous epithelium

lining part of the cyst cavity, with or without luminal

and/or mural tumor growth hence, UA should be

differentiated from odontogenic cysts and also

should be recognized for the reason that the former

has a higher rate of recurrence than the latter12.

Ackermann et al have provided a histological

subgrouping of the Unicystic Ameloblastoma as

shown in (Table 1) and a diagrammatic

representation of the same shown in (F ig. 12).2The

UAs diagnosed as subgroups 1 and 1.2 can betreated

conservatively (careful enucleation), whereas

subgroups 1.2.3 and 1.3 showing intramural growthsrequire treated radical resection, as for a solid or

multicysticameloblastoma.13Following enucleation,

vigorouscurettage of the bone should be avoided as

it mayimplant foci of ameloblastoma more deeply

Unicystic Ameloblastoma Aniket J ain, et, al.

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into bone. Chemical cauterization with Carnoys

solution is also advocated for subgroups 1 and 1.2.

Subgroups 1.2.3 and 1.3 have a high risk for

recurrence, requiring more aggressive surgicalprocedures. This is because the cystic wall in these

cases has islands of ameloblastoma tumor cells and

there may be penetration into the surrounding

cancellous bone.14,15

Recurrence is always an aspect to look after

resection specially in the case of unicystic

ameloblastoma. Lau et al reported recurrence rates

of 3.6% for resection, 30.5% for enucleation alone,

16% for enucleation followed by Carnoys solution

application, and 18% by marsupialization followed

by enucleation.16 Recurrence rates are also related

to the histologic subtypes of UA, with those invading

the fibrous wall having a rate of 35.7%, but others

only 6.7%.15 Vascularised fibula graft was first

described by Taylor in 1975, and in 1989 Hidalgo

first used free fibula flap in mandibular

reconstruction.17 Later Chen and Yen incorporated

an overlying skin paddle for composite

reconstruction of the bone and soft tissue defect.18

After demonstrating that osteotomies can be

performed in vascularised fibula grafts without

compromising the viability of the bone segment,

vascularised free fibula flap became the state of art

reconstruction method after mandible ablation.

Normally if the tumour is small (< 5cm) the defectcan be repaired with a free bone graft. However,

the tumour is often larger and a large defect

reconstruction is challenging and may require a

microsurgical flap either from fibula, iliac crest,

scapula, radius or ribs. Since this patient has a large

bony defect, a free fibula osteoseptocutaneous flap

was chosen to address both the bony and soft tissue

defect.

Conclusion:

The diagnosis of unicystic ameloblastoma was

based on clinical, radiological and histopathologic

features. Unicystic ameloblastoma is a tumor with

a strong propensity for recurrence, hence the

Pathologist should examine the tissue sections

carefully for better prognosis of the treatment

outcome.

References:

1. Gerzenshtein J , Zhang F, Caplan J , Anand V, L ineaweaver

W: Immediate mandibular reconstruction with microsurgical

fibula flap transfer following wide resection forameloblastoma. J Craniofac Surg 2006;17(1):178-182.

2. Ackermann GL, Alti ni M, Shear M . The unicysticameloblastoma: A clinicopathologic study of 57 cases. J OralPathol 1988; 17: 541-546

3. Phil ipsen HP , Reichart PA. U nicystic ameloblastoma: areview of 193 cases from the literature. Oral Oncol 1998;34(5):317-325.

4. Phi lipsen HP, Reichart PA: Classification of odontogenictumors and allied lesions. Odontogenic tumors and alliedlesions Quintessence Pub. Co. Ltd 2004;21-23.

5. Chana, J agdeep S, Yang-Ming Chang, Wei, Fu-Chan, Shen,Yu-Fen, Chan Chiu-Po, L in Hsiu-Na, Tsai Chi-Ying, J engSeng-Feng: Segmental mandibulectomy and immediate freefibula osteoseptocutaneous flap reconstruction withendosteal implants: An ideal treatment method formandibular ameloblastoma. Plast Reconstr Surg 2004;113(1):80-87.

6. Phil ipsen HP, Reichart PA. Unicystic ameloblastoma. In:Odontogenic tumors and allied lesions. QuintessencePub.Co.Ltd, 2004; 77-86.

7. Srinivasan H, Arathy Manohar. Unicystic ameloblastoma ofthe mandible: A case report. Annals and Essence of Dentistry2010; 2(4):75-77.

8. Navarro CM, P rincipi SM, Massucato EM , Sposto MR.Maxillary unicystic ameloblastoma. Dentomaxillofac Radiol2004;33:60-62.

9. Sapp J P. Contemporary Oral and Maxill ofacial Pathology(2nd ed) USA: Mosby 2004.

10. Phi li psen HP , Reichart P A. U nicystic ameloblastoma.Odontogenic tumors and allied lesions. London: QuintessencePub. Co. L td 2004; 77-86.

11. Pizer ME , Page DG, Svirsky J A. Thirteen-year follow-up oflarge recurrent unicystic ameloblastoma of the mandible ina 15-year-old boy. J Oral Maxillofac Surg 2002; 60:211-215.

12. Ramesh Rakesh S, Manjunath Suraj, U stad H Tanveer, etal. U nicystic ameloblatoma of the mandible-an unusual casereport and review of literature. Head and Neck Oncology2010; 2:1.

13. Phi li psen HP , Reichart P A: U nicystic ameloblastoma.Odontogenic tumors and all ied lesions London: QuintessencePub. Co. L td 2004; 77-86.

14. L i TJ , Ki tano M, Arimura K, Sugihara K: Recurrence ofunicystic ameloblastoma: A case report and review of theliterature. Arch Pathol Lab Med 1998;122:371-374.

15. L i T , Wu Y, Y u S, Yu G: Clinicopathological features ofunicystic ameloblastoma with special reference to itsrecurrence. Zhonghua Kou Qiang Y i Xue Za Zhi 2002; 37:210-212.

16. Lau SL , Samman N: Recurrence related to treatmentmodalities of uni cystic ameloblastoma: A systematic review.Int J Oral Maxill ofac Surg 2006; 35:681-690

17. Taylor GI, Mil ler GD, Ham FJ . The free vascularized bonegraft: A clinical extension of microvascular techniques. PlastReconstr Surg 1975; 55(5): 533-544.

18. Chen ZW, Yan W. The study and clinical application of theosteocutaneous flap of fibula. Microsurgery 1983; 4(1): 11-16


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Table 1: Showing Akermans grouping of UA and their interpretation

Subgroup Interpretation

1 Luminal UA1.2 Luminal and Intraluminal UA

1.2.3 Luminal, Intraluminal and Intramural UA

1.3 Luminal and Intramural UA

Figure 1: Facial Profile showing facialasymmetry on the left side

Figure 2: Diffuse overgrowth seen in lower leftposterior alveolar and vestibular region

Figure 3: OPG showing extent of lesion involvingbody, angle and ramus upto the condyle

Figure 4: Lateral view of body of mandibleshowing the extent of lesion

Figure 5: Exposure of the lesion via extendedrisdons incision

Figure 6: Resected specimen afterhemimandibulectomy

Figure 7:Retrieval and shaping of fibula graft withthe help of osteotomies and mini plates and screws

Figure 8:Post operative radiograph showing free fibulagraft secured at the recipient site with plates and screws

Figure 9: Histopathologic picture of the resected specimen showingtypical ameloblastomatous epithelium lining part of the cystic cavity

Figure 10: 18 months post operative radiographicpicture showing graft in place, mimicking the lower jaw

Figure 11: 18 months post operative intraoralview showing well adaptation of graft

Figure 12: Showing Ackermans grouping of UA asfollows: 1) Luminal, 2) Intraluminal, 3) Intramural


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