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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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Indian J Dent Adv 2012; 4(2) 844
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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Indian J Dent Adv 2012; 4(2) 845
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
Unicystic Ameloblastoma Aniket J ain, et, al.