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Clinical
Paper
Clinical Pathology
Juvenile ossifying fibroma of the jaw: a retrospective study of 15cases J.
Han,
L.
Hu,
C.
Zhang,
X.
Yang,
Z. Tian,
Y.
Wang,
L. Zhu,
C.
Yang,
J.
Sun,
C.Zhang,
J.
Li,
L. Xu:
Juvenile
ossifying
fibroma
of
the
jaw:
a
retrospective
study
of
15cases. Int. J. Oral Maxillofac. Surg. 2016; 45: 368–376. # 2015 InternationalAssociation of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rightsreserved.
J.
Han1,5,
L.
Hu1,5,
C.
Zhang2,X.
Yang1,
Z.
Tian2,
Y.
Wang1,
L.
Zhu3,C.
Yang4,
J.
Sun1,
C.
Zhang1,
J.
Li2,L.
Xu1
1Department of Oral and Maxillofacial–Headand Neck Oncology, Ninth People’s Hospital,Shanghai Jiao Tong University School ofMedicine, Shanghai, China; 2Department ofOral Pathology, Ninth People’s Hospital,
Shanghai Jiao Tong University School ofMedicine, Shanghai, China; 3Department ofRadiology, Ninth People’s Hospital, ShanghaiJiao Tong University School of Medicine,Shanghai, China; 4Department of OralSurgery, Ninth People’s Hospital, ShanghaiJiao Tong University School of Medicine,Shanghai, China
Abstract. The management of patients with juvenile ossifying fibroma (JOF) remainscontroversial.
To
explore
the
correlations
between
different
treatments
and
the patient
prognosis,
15
cases
of
JOF
of
the
jaw
were
reviewed.
Five
patients
weremale and 10 were female. Patient age at the time of disease onset ranged from 7 to18 years (mean 10.9 years). Nine tumours were located in mandible and six in themaxilla.
These
cases
typically
manifested
clinically
as
painless
swelling
of
the
jaw(9/15,
60%);
40%
(6/15)
of
the
cases
were
associated
with
pain,
diplopia,
stuffynose, and/or rapid growth. Images of JOF can show a radiolucent, mixed, or ground glass-like appearance. Pathological examinations revealed 10 cases of juveniletrabecular
ossifying
fibroma
(JTOF)
and
five
cases
of
juvenile
psammomatoid ossifying
fibroma
(JPOF).
In
terms
of
the
treatment
plan,
six
patients
initiallyreceived radical surgery; nine patients underwent conservative treatment, amongwhom six (6/9, 66.7%) had one or more recurrence. At the end of the follow-up period,
12
patients
had
no
evidence
of
tumour
recurrence
and
three
cases
were
alivewith
a tumour.
In
summary,
surgeons
should
develop
the
surgical
plan
according
tothe extent of the lesion, relapse status, growth rate, and family choice, and these patients should be followed up closely.
Key words: jaw; JOF; JPOF; JTOF; treatment.
Accepted for publication 7 December 2015Available online 28 December 2015
Ossifying fibroma (OF) is a type of benignfibro-osseous lesion. This tumour is char-acterized
by
clear
boundaries
and
cell-richfibrosis,
and
contains
varying
amounts
of
calcified tissue resembling bone, cemen-tum, or both. OF lesions are classified asconventional
ossifying
fibroma
and
juve-nile ossifying
fibroma
(JOF).1 Conven-
tional OF is mainly seen in adults. JOFusually occurs in children or adolescents,
and it is therefore also known as juvenileactive/aggressive ossifying fibroma(JAOF).
In
2005,
the
World
Health
Orga-nization
(WHO)
noted
that
the
age
at
onset
of JOF is 15 years and younger.1However,
JOF has also been documented in adults.2,3
JOF
has
characteristics
of
aggressivegrowth,
is
associated
with
damage
to
the
cortical bone, and may involve the nasalcavity, eyes, and even cerebrum. Howev-
er, there are no reports of cases of malig-nant transformation or metastasis. Theimaging
characteristics
of
JOF
show
ex- pansive,
well-defined
radiolucent
or
mixed images that are separ ated fromthe surrounding normal bone.
4Based on
histopathology,
JOF
is
divided
into
the
Int. J. Oral Maxillofac. Surg. 2016; 45: 368–376 http://dx.doi.org/10.1016/j.ijom.2015.12.004, available online at http://www.sciencedirect.com
5 These authors contributed equally to thiswork.
0901-5027/030368+ 09 # 2015 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.
http://dx.doi.org/10.1016/j.ijom.2015.12.004http://dx.doi.org/10.1016/j.ijom.2015.12.004http://dx.doi.org/10.1016/j.ijom.2015.12.004http://dx.doi.org/10.1016/j.ijom.2015.12.004http://dx.doi.org/10.1016/j.ijom.2015.12.004
8/19/2019 Pi is 090150271501468 x
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following
two
subtypes:
juvenile
psammo-
matoid ossifying fibroma (JPOF) and juve-nile trabecular ossifying fibroma (JTOF). Inaddition, JOF usually contains multinucle-ated
giant
cells,
whereas
conventional
OF
does not.5,6Conventional OF usually pre-
sents as a slow-growing mass of bone ex- pansion that is usually without symptoms
and rarely recurs; conversely, 38.5% of JOFcasesare associated with mandibular swell-ing and pain and there may be short-termrapid growth.7 Therefore, surgeons should consider clinical features, radiological
characteristics, and pathological featureswhen diagnosing JOF. Key points to beconsidered include age, status of growth,
and histopathology.8
The management of patients with JOFremains controversial. According to theliterature, the recurrence rate after surgery
is approximately 30–58%.1,3,9–11
There-fore, designing an appropriate treatment
plan for
the
JOF
patient
could
help
toimprove the prognosis and quality of life.
Depending on biological behaviour and the lesions involved, treatment can be
conservative
or
radical.12 Some
research-
ers have emphasized the aggressivegrowth characteristics and high recurrencerate of JOF, lead ing them to advocate localradical
surgery.4,13,14 In
contrast,
others
consider that conservative treatment ismore beneficial for young patients whentaking into account their growth and de-
velopment, their appearance, and the pres-ervation of chewing and nervefunctions.
12,15,16
This study was performed to review theclinical features, imaging features, and
pathological characteristics of 15 casesof JOF treated at the authors’ institution.The relationships between the different
treatment options and the prognosis arediscussed and the most suitable treatmentsfor JOF are explored.
Materials
and
methods
A total of 15 patients with JOF treated between 2005 and 2014 in the Departmentof Oral and Maxillofacial–Head and Neck
Oncology of the study institution were
included.
Each
patient’s
medical
history
was reviewed carefully to collect clinicaldata (including age, sex, disease location,symptoms, surgical approach, and prog-nosis),
radiological
features,
histological
type, and other information.According to the anatomical location,
the mandible was divided into anterior
(left canine to right canine), posterior (first premolar to third molar), angle, ramus,and condyle. The maxilla was divided intoanterior (left canine to right canine) and posterior (first premolar to the maxillary
tuberosity). Imaging data were used toanalyze the lesion and surrounding tissue boundaries and the internal radiographic
architecture. The internal radiographic ar-chitecture was divided into mixed radi-opaque and radiolucent, unilocular or multilocular radiolucency, and ground
glass opaque. An oral pathology specialistclassified the histological subtype as either
JTOF
or
JPOF
based
on
the
2005
WHOclassification criteria for head and neck
cancer.1Surgeries performed included
conservative treatments (curettage and
Juvenile ossifying fibroma of the jaw 369
Table 1. Clinical information, treatment, and follow-up information for the 15 cases of juvenile ossifying fibroma (JOF).
Patient No./sex
Age atonset(years)
Age atoperation(years)
Size
Symptoms
Location
Surgery
Follow-up(months);outcome
Conservative treatment 1/M 8 8 4.5 4 Swelling Right maxilla Curettage 72; alive
with tumour 2/F 14 19 2 1.5 Swelling Left maxilla
(posterior)Curettage 20; alive
with tumour 3/M 13 13 5 4 Swelling Right mandible
(posterior)Enucleation 38; NED
4(R)/M
18
20
3
2
Swelling,
pain
Left
maxilla
Curettage
124;
alivewith tumour
5(R)/F 9 16 6 4 Swelling Right mandible(posterior)
Curettage/resection + fibula 95; NED
6(R)/F
12
15
5
4
Swelling
Left
mandible(posterior/angle)
Curettage/resection
+
iliac
crest
146;
NED
7(R)/M 15 17 9 8 Swelling,rapid growth
Right mandible(posterior)
Curettage/resection + fibula 105; NED
8(R)/M
10
12
10
7
Swelling,rapid growth
Left
mandible
Curettage/resection
+
fibula
40;
NED
9(R)/F 9 19 9 8 Swelling,stuffy
nose,diplopia
Right maxilla Curettage/resection + fibula 128; NED
Radical treatment
10/F 13 19 12 8 Swelling Left mandible(posterior)
Resection + fibula 87; NED
11/F 11 11 6 4 Swelling Right mandible(posterior)
Resection + iliac crest 58; NED
12/F 7 7 6 4.5 Swelling Left mandible(posterior/angle)
Resection + iliac crest 36; NED
13/F
7
7
3
2
Swelling
Right
mandible(condyle)
Resection
+
costal
cartilage
15;
NED
14/F 7 8 4 3.5 Swelling, pain,diplopia,rapid
growth
Left maxilla(posterior)
Resection 18; NED
15/F 11 15 6 4 Swelling, pain,rapid growth
Right maxilla Resection 13; NED
F, female; M, male; NED, no evidence of disease; (R), recurrence.
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enucleation) and radical surgery (com-
plete resection with or without reconstruc-
tion).Due to the retrospective nature of this
study, it was granted an exemption from
requiring ethics approval in writing by theinstitutional review board of the studyhospital.
Results
Clinical data
Of the 15 cases of JOF, five were male and
10 were female, giving a male to femaleratio of 1:2. The age at onset ranged from 7
to 18 years (mean 10.9 years). The ages of JTOF patients ranged from 9 to 13 years
(mean 11 years) and the ages of JPOF patients ranged from 7 to 18 years (mean10.9 years). The disease duration ranged
from 2 weeks to 5 years, with an average
of 18.2 months (Table 1).
The lesions
were
located
in
the
mandiblein nine cases and in the maxilla in six cases,with three involving the maxillary sinus. In
mandibular cases, the site was most often posterior (5/9, 55.6%), followed by a com- bination of posterior and angle (2/9,22.2%). For the upper jaw, unilateral in-
volvement of the entire maxilla (4/6,66.7%) was most common, followed bythe posterior of the maxilla (2/6, 33.3%).Sixty percent (9/15) of cases manifested
clinically as a slowly growing painlessmass in the jaw. Forty percent of cases(6/15; four cases involving the maxilla and
two involving
the
mandible)
presented with pain, diplopia, stuffy nose, and/or rapid growth. Clinical examinationrevealed an immobile hard mass, and
egg shell crackling was occasionally noted when a cystic lesion developed.
Before surgery, most patients had a
diagnosis of ossifying fibroma (10/15,
66.7%).
Other
diagnoses
included
amelo- blastoma (n = 2, 13.3%), fibrous dysplasia(n = 1, 6.7%), chondromyxoid fibroma
(n = 1, 6.7%) and aneurysmal bone cyst(n = 1, 6.7%).
Imaging features
Images of all patients showed a mass with
clear boundaries. There was generally nosoft tissue involvement. Computed tomog-raphy (CT) and/or panoramic images wereavailable for a total of 13 patients. Accord-
ing to the component and proportion of
soft tissue
and
hard
tissue
in
the
internalstructure, the tumour masses presented asmixed radiopaque and radiolucent (5/13,
38.5%), unilocular or multilocular radio-lucency (3/13, 23.1%), and ground glassopaque (4/13, 30.8%) (Table 2). Three of
370 Han et al.
Table 2. Radiographic features and pathology of 15 cases of juvenile ossifying fibroma (JOF).
Pathology Patient No. Radiographic features
JTOF
4
Ground
glass
opaque,
well-defined
border 6 Mixed radiopaque and radiolucent, well-defined border 7 Multilocular radiolucency, well-defined border 11 Mixed radiopaque and radiolucent, well-defined border 1 Mixed radiopaque and radiolucent, well-defined border 12 Unilocular radiolucency, well-defined border
8* Multilocular radiolucency, well-defined border 2 Not available13 Mixed radiopaque and radiolucent, well-defined border 14* Not available
JPOF 10 Ground glass opaque with central radiolucency, well-defined border 3 Mixed radiopaque and radiolucent, well-defined border 5 Ground glass opaque with central radiolucency, well-defined border 9 Multilocular
radiolucency
with
ground
glass
opaque,
well-defined
border 15 Ground glass opaque with central radiolucency, well-defined border
JTOF, juvenile trabecular ossifying fibroma; JPOF, juvenile psammomatoid ossifying fibroma.* JTOF with aneurysmal bone cyst.
Fig.
1.
Imaging
findings
in
juvenile
ossifying
fibroma
(JOF):
case
15.
(A)
Preoperative
axial
CT
showing
a
bulging
mass
in
the
maxilla,
a
ground glass-like appearance, and central cystic changes. (B) Preoperative sagittal CT showing a mass intruding into the maxillary sinus and rootdisplacement. There is a high-density shadow in the surrounding area.
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the ground glass opaque cases were asso-ciated with central radiolucent regions(Fig. 1), and one case had multiple radio-lucent regions associated with ground
glass plaques. CT imaging and three-di-
mensional
reconstruction
of
the
differentorientations showed cortical bone destruc-tion and absorption in nine cases (9/13,
69.2%), with adjacent tooth or root dis- placement in seven (7/13, 53.8%).
Histopathological features
General examination revealed that JOFwas usually a grey mass with a clear
boundary. Tumour sizes ranged from 2to 12 cm, with an average of 6.03 cm.Those with diameters 5 cm accounted for 66.7% (10/15) of cases. Dissection of
the tissue
showed
gravel-like
or
hard
tis-sue. Of the 15 cases of JOF, 10 were JTOFand five were JPOF (Table 2). Under themicroscope, JTOF demonstrated a cell-
rich fibrous tissue background with a stripof osteoid-containing cells or immaturetrabecular cells. The trabecular bone wassurrounded by a layer of hypertrophic
osteoblasts, which together formed agrid-shaped region. Some regions showed aggregations of osteoclast-like multinu-cleated giant cells. Twenty percent (2/
10) of cases were associated with an an-eurysmal bone cyst (Fig. 2A, C). JPOFwas characterized by fibroblastic stromaand basophils containing sand-like struc-
tures that resembled cementum (Fig. 2B).
Types of surgery and prognosis
All patients underwent surgical treatment,including conservative treatment and localradical surgery. Nine patients first under-
went conservative treatment, amongwhom six had one or more recurrence,giving a recurrence rate of 66.7% (6/9).Among those experiencing a recurrence,
five underwent local radical surgery and
one underwent local curettage. Cases 4, 5,6, and 7 had recurrence after 8 months, 2years, 6 months, and 11 months, respec-tively. Case 8 had local recurrences after
twice undergoing curettage, at 6 months
and
7
months
after
the
procedure.
Case
9had recurrences at 5 years and 15 monthsafter surgeries. Overall, recurrence oc-
curred at between 6 months and 5 years,with an average of 17.1 months. Six patients initially had local radical surgeryand none had a recurrence.
Nine patients underwent reconstructive
surgery.
One
patient
with
JOF
in
the
max-illa underwent a fibula muscle flap trans- plantation (Fig. 3). Of the eight mandible
Juvenile ossifying fibroma of the jaw 371
Fig. 2. Histopathological features of juvenile ossifying fibroma (JOF). (A) Juvenile trabecular ossifying fibroma (JTOF) (case 4) has a cell-richfibrous
tissue
background
with
cell-containing
immature
trabecular
bone.
A
layer
of
hypertrophic
osteoblasts,
which
form
a
grid-like
structure,surrounds the trabecular bone. (B) Juvenile psammomatoid ossifying fibroma (JPOF) (case 15) has a fibrous stroma containing sphericalmineralized bodies. The bodies are like cementum, with basophilic cores and an eosinophilic exterior. (C) Aneurysmal bone cyst formed withinJTOF (case 8). The capsule is filled with red blood cells.
Fig. 3. Imaging findings in juvenile ossifying fibroma (JOF): case 9. (A) The lesion recurred after multiple maxillary curettages. Axial CT showing multiple transparent shadows accompa-nied
by
ground
glass-like
plaques.
(B)
CT
reconstruction
revealing
lesions
involving
the
nasalcavity and orbital cavity, as well as cortical discontinuity. (C) Immediate CT three-dimensionalreconstruction after maxillary expansive resection and fibula muscle flap transplantationshowing
ideal
recovery
of
the
jaw
morphology.
(D)
Axial
CT
showing
a
metal
plate
of
thecorrect shape without evidence of recurrence at 1 year and 2 months after surgery.
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cases,
three
underwent
a
free
iliac
crest
graft (Fig. 4), one case with condyle in-volvement had a costal cartilage trans- plantation (Fig. 5), and four casesunderwent
fibula
flap
transplantation
(Fig. 6).The 15 patients were followed up for
13–146 months, with an average follow-
up of 66.3 months. The follow-up of patients with multiple surgeries wasrecorded from the date of the initial sur-gery (Table 1). All patients were alive atthe end of follow-up: 12 patients had no
evidence of disease (tumour-free survival)and three patients were living withtumours.
Discussion
JOF is a variant of OF that occurs mainly
in the cranial and facial bones of young patients. JOF can lead to severe morpho-
logical
and
functional
defects.
JOF
and other benign fibrous lesions have great
similarities in terms of their clinical fea-tures, imaging characteristics, and pathol-ogy. Therefore, a systematicunderstanding of the disease can enable
clinicians to perform an accurate diagno-sis, develop a reasonable treatment plan,and predict the prognosis. This study ret-rospectively analyzed 15 cases of JOF
with regards to their clinical, radiological,and pathological features and analyzed the prognoses associated with the differenttreatment options. The aim was to develop
more
appropriate
treatment
methods.
Thisstudy reports on JOF in a relatively largecohort of Chinese patients.OF can occur at any age, but is mainly
seen in adults aged 30–40 years. JOF patients are relatively young. In the2005 WHO definition, the age at onsetof JOF is 15 years. However, according
to a report by Johnson et al., the age atonset of JOF ranges from 3 months to 72years.
3Studies reported in the literature
have indicated that the average age atonset of the two JOF subtypes differ s:the age at JPOF onset is 10 to 25 years,
10
whereas JTOF patients are relatively
younger, at 8.5–12 years.4The ages of
the patients with the two subtypes in the present study were similarly young: theaverage age of JTOF patients was 11 years
and the average age of JPOF patients was10.9 years. In terms of the sex distribution,various case reports in the literature haveshown a slight difference.
3,5In the present
group of patients, JOF was more common-ly seen in females, with a male to femaleratio of 1:2.JTOF usually occurs in the jaw,
4where-
as JPOF occurs mainly in the paranasal
sinus bone wall.3,17
There are a f ew casereports of JPOF in the jaw.
2,18In this
study, the lesions in the 15 patients withJOF (10 cases of JTOF and five cases of JPOF) all occurred in the jaw. Different
reports
have
shown
different
sites
of
dis-ease onset.5,19,20
In this study, there wereslightly more patients with disease in thelower jaw (nine cases) than in the upper
jaw (six cases).Locally aggressive growth is an impor-
tant clinical feature that differentiates JOFfrom conventional OF. It has been
reported that 38.5% of JOF patients haveswelling with pain,
7while conventional
OF is associated with painless swelling inthe jaw. When the tumour is located in the
upper jaw and becomes large, it can in-volve the surrounding tissues such as theeyes
17,21and nasal cavity,
22thereby
resulting in exophthalmos, nasal conges-
tion, and other symptoms. In the group of patients presented here, 40% (6/15; four cases involving the maxilla and two in-volving the mandible) had pain, diplopia,
stuffy nose, and/or rapid tumour growth.The imaging characteristics of this
group of JOF patients were found to besimilar to those reported in the litera-
ture.4,23
According to the internal compo-nents of hard and soft tissue, tumours can present as radiolucent, mixed, opaque, and ground glass-like. There is a high-density
boundary between the lesions and thesurrounding normal bone. The imaging
characteristics are often associated withhistological types.
23JPOF usually resem-
bles ground glass and JTOF usually looks
like mixed
or
radiolucent
shadows.
Thisgroup of cases had similar features. Pa-thologies that need to be distinguished from JOF using imaging studies include
fibrous dysplasia, osseous dysplasia,odontoma, and ameloblastoma. Althoughfibrous dysplasia can resemble ground glass, it usually has unclear boundaries
and may involve multiple bones. Osseousdysplasia usually presents as calcificationin the space between the roots or as acotton-like calcification involving the bi-
lateral upper and lower jaws. Odontomaand ameloblastoma are also common inyounger patients, although odontoma usu-ally presents as a mass with mixed densi-
ties around the roots, with clear boundaries and visible non-erupted teethor shadows of teeth of varying sizes.Ameloblastoma usually presents as multi-
ple radiolucent regions with discrete, cor-ticated borders. Aneurysmal bone cystassociated with JOF is reported wide-ly,
3,4,10,24,25and this is more common in
young patients and shows levelled fluid under CT examination.
10In this study,
there were two cases of JTOF with aneu-rysmal bone cyst. These two patients were
372 Han et al.
Fig. 4. Imaging findings in juvenile ossifying fibroma (JOF): case 11. (A) Preoperative panoramic radiograph showing a bulging body in the right mandible. (B) Four years after mandibular segmental resection and iliac bone graft, the mandible is in good shape with noevidence
of
recurrence.
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10 years and 7 years old at onset, which isconsistent with findings in the literature.Conventional OF lesions usually have
limited regions and clear boundaries.Patients usually undergo surgical excisionof the tumour. Recurrence is rare and the prognosis is good. However, there is cur-
rently no consensus on the treatment planfor JOF. Clinical treatments can be divid-ed into conservative and radical treat-ments, and the histological subtype has
no effect on treatment options. Consider-ing the aggressive growth pattern and highrecurrence rate of JOF, some researchersadvocate local radical surgery to
completely remove as much of the in-volved tissue as possible while preservingthe important surrounding structures. Nev-ertheless, excessive removal of the sur-
rounding nor mal bone tissue is notrecommended.
4,13,14Conservative treat-
ments including curettage, enucleation,and partial resection, aim to limit facial
deformity and dysfunction and preservegrowth and development, a normal ap- pearance, and chewing and nerve func-tions in young patients.
12,15,16When
aggressive growth is obvious, which ismarked by rapid growth, cortical thinningor perforation, and the displacement of
teeth or root resorption, the patient should undergo complete resection.
12
In a recent study, researchers found thatthe simultaneous amplification of MDM2
(E3 ubiquitin-protein ligase gene) and RASAL1 (RAS protein activator like 1gene) was significantly higher in juvenileossifying fibromas compared with non-
juvenile ossifying fibromas. Moreover,among the nine cases of JOF withMDM2 and RASAL1 amplification, threedemonstrated local invasiveness or rapid
growth and four were recurrent. This ab-normality is not only a potential molecular diagnostic marker, but may also be indic-ative of aggressive forms of the disease
with a higher risk of recurrence,26and
therefore may indicate a more radicaltreatment plan.As JOF patients are relatively young,
clinicians should aim to maintain or re-store the patient’s appearance during treat-ment to reduce the impact on their growthand development. Individualized treat-
ment plans were developed for each pa-tient in the present study, after takingvarious factors into account. These factors
included the site of the lesion, involve-ment of the surrounding vital tissue, pa-tient age, growth rate, and parental choice.Of the 15 patients, nine initially underwent
conservative treatment and six received local radical surgery.In cases of large or rapidly growing
lesions, among others, complete resec-
tion should be chosen as the initial sur-gery. Additionally, due to the anatomicalstructure, maxillary lesions often involvethe nose, eyes, skull, and other tissues;
this makes complete resection difficult.Meanwhile, with relatively less impor-tant structures around mandibular lesions, segmental resection is not al-
ways necessary. Take case 3 for exam- ple: the lesion had a limited range, therewere clear boundaries between the lesionand the surrounding normal bone, and
the jawbone cortex had continuousedges; in this case enucleation of thetumour achieved a good prognosis(Fig. 7).
Juvenile ossifying fibroma of the jaw 373
Fig.
5.
Imaging
findings
in
juvenile
ossifying
fibroma
(JOF):
case
13.
(A)
Preoperative
panoramic
radiograph
showing
a
transparent
shadow
in
theright condylar region, with clear boundaries. (B) Preoperative coronal CT showing shadows of mixed densities in the right condylar region. (C) Sixmonths after condylar tumour resection and cartilage repair, the shape of a metal plate is partially seen, and there is no evidence of recurrence. (D)Postoperative CT reconstruction showing good recovery of jaw shape.
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According to reports published in theliterature, the recurrence r ate after surgery
is approximately 30–58%.1,3,9–11
The totalrecurrence rate calculated from the presentdata is 40% (6/15), with the rate after conservative treatment being high at
66.7% (6/9) and the rate following radicalsurgery being zero. Since malignancieshave not been reported, these neoplasmscan safely be left when they are in a stable
state. In this study, three patients werealive with the tumour at the end of fol-low-up, and the tumour did not showobvious enlargement.
Defect reconstruction can be carried out at the time of excision 13,27–29or in a
second-stage procedure.30
There arereports of no repair or of immediaterepair using a reconstruction plate torestore the appearance after resection
of JOF.18,31
In this study, a total of nine patients underwent immediate recon-struction after resection. Based on thesite and size of the defect, three methods
of restoration were used, includingvascularized fibula flap transplantation(five cases), free iliac crest graft(three cases), and costal carti lage
transplantation to repair the condylar region (one case).
According to a report by Johnson et al.,aggressive growth characteristics of JOFlesions are mainly observed in the maxil-la.
3The anatomy of the maxilla prevents
the tumours at this site from being re-moved easily and completely, resultingin a high rate of relapse and difficultieswith reconstruction. In this study, among
patients who had lesions in the maxilla,only one (case 8) had single-side maxillaresection and fibula flap transplantation.The remaining eight patients who
374 Han et al.
Fig.
6 .
Imaging
findings
in
juvenile
ossifying
fibroma
(JOF):
case
8.
(A)
The
mandibular
lesion
relapsed
after
curettage.
Panoramic
radiographshowing a mixed shadow containing incomplete permanent crowns. (B) The lesion expanded 7 months after a second curettage. (C) Sagittal CTshowing transparent shadows with mixed densities. (D) Axial CT showing significant bulging in the lingual mandibular cheek. (E) CTreconstruction
revealing
severe
bone
destruction
and
cortical
discontinuity.
(F)
Two
years
and
1
month
after
mandibular
segment
resection
and fibula flap transplantation, there was no evidence of recurrence.
8/19/2019 Pi is 090150271501468 x
8/9
underwent reconstruction had mandibular defects. At the end of follow-up, all
patients with maxillofacial reconstructionhad recovered their appearance and therewere no signs of recurrence. Therefore, it
is speculated
that
reconstruction
can
be performed concurrently with preservingthe safety margins of the excision. Al-though there has been no report of malig-
nant transformation, the physician should be more cautious when choosing the tim-ing of r econstruction for rapidly growinglesions.
17
In summary, JOF of the jaw is a type of uncommon benign fibro-osseous lesion. IntheChinese population, JOF is more com-monly seen in females than in males and
may occur in children or adolescents. JOFhas two histological subtypes, which areJPOF and JTOF; JTOF is more common inthe jaw. Its imaging characteristics include
a radiolucent or mixed density appearancemarked by clear boundaries. The diagno-sis requires consideration of a combina-tion of factors such as age, growth pattern,
imaging features, and pathology. Al-though JOF has aggressive characteristicsand a high recurrence rate (40%, 6/15),malignancies have not been reported.
Therefore, initial conservative surgicaltreatment is recommended, but a radicalapproach is warranted for lesions that behave destructively, that present rapid
growth, where there is pain and displace-ment of teeth, and for lesions with one or
more recurrence. In addition, as the recur-rence rate following conservative treat-ment is high at up to 66.7% (6/9), long-
term
follow-up
and
vigilance
is
indicated.
Funding
This
work
was
supported
by
researchgrants
from
Shanghai
Jiao
Tong
Universi-
ty Cross Research Fund for Medical and Science (YG2012MS42), the Science and Technology
Commission
of
Shanghai
Mu-nicipality
(15411950300),
and
the
Shang-
hai Natural Science Foundation of China(13ZR1457100).
Competing interests
None.
Ethical
approval
Due to the retrospective nature of thisstudy, it was granted an exemption inwriting
by
the
Institutional
Review
Board of
the
Ninth
People’s
Hospital.
Patient
consent
Not required.
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Juvenile ossifying fibroma of the jaw 375
Fig. 7 . Panoramic radiographs of juvenile ossifying fibroma (JOF): case 3. (A) Before surgery,JOF presented
as
a
single
transparent
shadow
in
the
right
mandible.
There
were
spots
of
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