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J Oral Maxillofac Surg70:2007-2012, 2012

Ameloblastic Fibrosarcoma: Report of aCase, Study of Immunophenotype, and

Comprehensive Review of the LiteratureJonathan Lai, MD,* Nick Blanas, DDS,† Kevin Higgins, MD,‡

and Hagen Klieb, DMD§

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Ameloblastic fibrosarcoma (AFS) is a rare odontogenicneoplasm exhibiting a benign ameloblastomatous ep-ithelial component admixed within a sarcomatousmesenchyme. It is considered the malignant counter-part of ameloblastic fibroma (AF) and can arise denovo or from transformed AF.1 AFS is a locally aggres-sive tumor that seldom metastasizes. According to theWorld Health Organization classification, AFS is consid-ered an odontogenic sarcoma. Other entities that fallunder this category include ameloblastic fibrodentinosar-coma (AFDS), ameloblastic fibro-odontosarcoma (AFOS),and odontogenic carcinosarcoma (OCS). AFDS and AFOSare considered counterparts of AFS because they sharethe same histologic features, but they have additionaldysplastic dentin and enamel and dentin, respectively.OCS has both a malignant ameloblastomatous compo-nent and a malignant mesenchyme. Clinically, all assumethe same locally aggressive course as AFS. Previous stud-ies have considered AFDS, AFOS, and AFS as 1 entityknown as ameloblastic sarcoma.2 However, in the con-ext of this report, we will consider AFS as an entity thatossesses ameloblastomatous epithelium within a sarco-atous mesenchyme, with no evidence of dentin or

namel elements present (Table 1).

Case Report

A 17-year-old female patient was referred for assess-ment of a left facial swelling of 2 years’ duration. A recent

*Department of Laboratory Medicine and Pathobiology, Univer-

sity of Toronto, Toronto, Ontario, Canada.

†Department of Dentistry (Oral and Maxillofacial Surgery), Sun-

nybrook Health Sciences Centre, Toronto, Ontario, Canada.

‡Department of Otolaryngology, Sunnybrook Health Sciences

Centre, Toronto, Ontario, Canada.

§Departments of Anatomical Pathology and Dentistry, Sunny-

brook Health Sciences Centre, Toronto, Ontario, Canada.

Address correspondence and reprint requests to Dr Klieb: Sunnybrook

Health Sciences Centre, 2075 Bayview Ave, Room H1-26, Toronto, On-

tario M4N 3M5, Canada; e-mail: hagen.klieb@sunnybrook.ca

© 2012 American Association of Oral and Maxillofacial Surgeons

278-2391/12/7008-0$36.00/0

oi:10.1016/j.joms.2011.09.012

2007

escalation in growth rate and new-onset dull painprompted her to seek care. She was otherwise in goodhealth. On examination, there was no palpable cervicallymphadenopathy. There was a bony hard swelling overthe left body of the mandible (Fig 1A). There was nofacial paresthesia. Intraorally, the left posterior mandib-ular alveolus was expanded and tooth 3.7 was laterallydisplaced from the dental arch but immobile (Fig 1B).

lain films showed a well-demarcated and partially corti-ated, multilocular radiolucency affecting the left poste-ior mandible (Fig 2A) with buccolingual alveolar expan-ion (Fig 2B).

The initial resection specimen was obtained by a par-ial mandibulectomy and measured 9.0 cm � 7.0 cm �.5 cm. Histologically, there were irregular islands andtrands of ameloblastomatous odontogenic epitheliumith typical peripheral palisading and reverse polariza-

ion embedded within a loosely cellular collagenoustroma typical of AF. Focally and representing no morehan 10% of the tumor volume, there were areas oftromal hypercellularity that merged with the AF compo-ent (Figs 3A,B). Such hypercellular areas were com-osed predominantly of spindle and polygonal cells withuclear atypia, pleomorphism, hyperchromasia, and oc-asional mitotic figures (2 of 10 high-power fields) (FigC). The benign ameloblastomatous epithelium was in-onspicuous. There was invasion through the lingualortex of the mandible with extension into the adjacentoft tissues and around the salivary gland ducts. On im-unohistochemical studies, the atypical mesenchymal

ells showed diffuse nuclear reactivity for p53 and Ki-67nd diffuse cytoplasmic reactivity for Bcl-2, MSA, andimentin. The mesenchymal areas more typical of AFhowed only faint and focal staining with these markers.he benign ameloblastomatous component showed cyto-lasmic positivity for pankeratin and focal staining forcl-2 and p53. No staining was observed for CD34,D117, desmin, and smooth muscle actin.The histologic features were those of AFS. A segment of

he left mandible, measuring 6.8 cm � 4.0 cm � 2.8 cm,as re-excised. The histology was similar, and the marginsere widely clear. The patient remains under observation,

nd there were no signs of recurrence at 6 months.

Discussion

In the context of odontogenic tumors, fewerthan 5% are malignant and even fewer are sarcoma-tous.3-5 To our knowledge, there have been 69, 3,12, and 5 reported cases of AFS, AFDS, AFOS, and

OCS, respectively, as of 2011 in the English-lan-

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Table 1. SUMMARY OF PREVIOUS AFS CASES REPORTED IN LITERATURE AS OF 2010

Author YearAge(yr) Gender Location Recurrence Metastases Death

De NovoAFS

PreviousAF Follow-Up

rompecher18 1918 13 M Mandible No No Yes* NA NA NAPapadimitrou19 1928 28 F Mandible No No No NA NA 6 moKegel20 1932 45 M Maxilla NA NA NA NA NA NAHauenstein21 1937 NA M Mandible NA NA NA NA NA NAEmminger22 1946 52 M Mandible No No No NA NA 3 moHertz23 1952 38 F Maxilla Yes No No NA NA 12 yrPindborg24 1960 17 M Left maxilla Yes No Yes Yes No 26 moCina et al25 1962 39 M Right mandible Yes No No No Yes 15 yr

1962 32 F Right mandible Yes No Yes No Yes 30 moMuroya and Shigematsu26 1962 43 M Mandible Yes No Yes NA NA 33 moCataldo et al27 1963 78 F Left mandible NA NA NA Yes No NFUHogeman and Willmar28 1966 30 M Right posterior mandible Yes No No No Yes 3 yr

eychl and Sazama29 1971 17 F Right maxilla Yes No Yes Yes No 4.5 yrLeider et al30 1972 26 F Right mandible Yes No No No Yes 16 yr

1972 43 M Left mandible Yes No No No Yes 38 mo1972 9 M Left mandible No No No Yes No 62 mo1972 22 F Left maxilla No No No Yes No 42 mo1972 23 F Left mandible Yes No No No Yes 34 mo1972 12 F Left maxilla Yes No NA No Yes NFU

Mori et al31 1972 3.5 F Right posterior mandible Yes No Yes Yes No 5 yr1972 40 F Left mandible Yes No Yes No Yes 19 yr

atzifotiadis and Economou32 1973 15 M Left posterior maxilla Yes No Yes Yes No 2 yrotegi et al33 1975 29 M Maxilla No No No NA NA 3 yr

Remagen et al34 1975 24 M Mandible NA NA NA NA NA NFUMatsumura et al35 1976 25 F Maxilla No NA NA NA NA NAGoldstein et al 1976 37 M Left mandible Yes No Yes† No Yes 4 yrAdekeye et al36 1978 26 M Right maxilla No No No Yes No 9 moReichart and Zobl37 1978 16 M Left mandible Yes No No No Yes 23 moDaramola et al38 1979 19 M Right posterior mandible No No Yes‡ Yes No NFUPrein et al39 1979 24 M Anterior mandible No No No NA NA 4 yrIwasa et al40 1981 24 F Mandible No NA NA NA NA NAChomette et al41 1983 9 NA Left maxilla Yes No No No Yes 10 mo

1983 38 M Right mandible Yes No No No Yes 3.5 yr1983 27 M Paramedian mandible Yes Yes Yes No Yes 10 yr

asu et al42 1984 24 F Right mandible No No No Yes No 4 yr1984 29 M Left maxilla No No No Yes No 9 yr

Takeda et al4 1984 19 M Left maxilla Yes No Yes No Yes 9.5 yrYamamoto et al43 1987 7 F Right mandible No No No No Yes 53 moWood et al44 1988 19 M Right mandible No No No Yes No 4 moSözeri et al3 1993 5 M Right mandible Yes No No No Yes 10 moDallera et al45 1994 34 M Right mandible Yes No No Yes No 15.5 yr

1994 18 F Right mandible Yes No Yes Yes No 1 yr1994 25 M Right mandible Yes No No No Yes 9 yr1994 18 F Right mandible No No No No Yes 2 yr1994 44 M Left mandible No No No No Yes 55 mo

Muller et al46 1995 53 F Left maxilla Yes No No No Yes 12 mo1995 17 F Right mandible No No No Yes No 1 yr1995 21 M Left mandible No No No No Yes 8 yr1995 57 F Left mandible Yes No No No Yes 6 yr

Park et al14 1995 17 M Right mandible Yes No Yes Yes No 3 moNogueira Tde et al13 1997 39 F Right maxilla No No No No Yes 2 yrTajima et al10 1997 14 M Right maxilla Yes No Yes Yes No 6 moDeNittis et al12 1998 32 M Right maxilla No No No Yes No 8 moLu et al47 1998 NA NA NA NA NA NA NA NA NA

1998 NA NA NA NA NA NA NA NA NA1998 NA NA NA NA NA NA NA NA NA

ayashi et al48 1999 22 M Left mandible No No No Yes No 3 yrBregni et al6 2001 19 M Left mandible No No No Yes No 7 moHuguet et al15 2001 31 M Mandible No No No Yes No 5 yrDufau et al49 2002 89 M NA Yes NA NA No Yes 1 mo, then LFU

osqueda Taylor et al5 2003 32 M Left mandible No No No Yes No NFUBatista de Paula et al16 2003 25 M Left mandible No No No Yes No 16 moYamaguchi et al50 2004 31 M Mandible Yes No Yes NA NA NALee et al51 2005 62 F Right maxilla NA NA NA NA NA NAKobayashi et al7 2005 26 M Left mandible Yes No No No Yes 5 yrWilliams et al11 2007 48 M Left maxilla Yes No No No Yes 6 moKousar et al52 2009 20 F Left mandible Yes Yes Yes No Yes 15 moGuthikonda et al9 2009 19 M Right mandible Yes No No No Yes 10 yrPontes et al53 2010 9 F Right mandible No No No Yes No NFU

Abbreviations: F, female; LFU, lost to follow-up; M, male; NA, not available; NFU, no follow-up.*From tuberculosis after operation.†From melanoma.‡From bleeding 9 days postoperatively.

Lai et al. Ameloblastic Fibrosarcoma. J Oral Maxillofac Surg 2012.

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Lai et al. Ameloblastic Fibrosarcoma. J Oral Maxillofac Surg 2012.

LAI ET AL 2009

FIGURE 2. A, Partially corticated, multilocular lucency affecting left posterior mandible. B, Buccolingual alveolar expansion.

FIGURE 1. A, Inferior view of patient during clinical assessment showing swelling over left posterior mandible. B, Intraoral examinationhowing left alveolus expansion with displacement of tooth 3.7.

ai et al. Ameloblastic Fibrosarcoma. J Oral Maxillofac Surg 2012.

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guage literature. Previous reports suggest that up toone-third of AFSs arise from transformation of AF.6,7

However, our review of the literature yielded 49 of69 cases of AFS that indicated the presence or

FIGURE 3. A, AFS with islands of benign ameloblastic epitheliumreas in continuity with AFS consistent with metastatic transformahould be noted. C, Higher-power view of AFS showing cellularhowing diffuse nuclear Ki-67 staining. E, Sarcomatous mesenchy

ai et al. Ameloblastic Fibrosarcoma. J Oral Maxillofac Surg 201

absence of a previous AF. Of these 49 cases, 25

(51%) had previously documented AF at the samesite, supporting evidence of malignant transforma-tion and the need for patients with AF to receiveappropriate clinical observation. The posterior

dded within highly cellular sarcomatous mesenchyme. B, AF-likee increase in mesenchymal cellularity from AF-like areas to AFS

matous mesenchyme with mitoses. D, Sarcomatous mesenchymewing focal positive nuclear p53 staining.

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LAI ET AL 2011

are locally aggressive and have a propensity toerode through bony structures and adjacent softtissues, with reports of skull base,8 orbital,9,10 andntracranial invasion.8,9,11 AFS more frequently af-ects male patients, with a male-to-female ratio of.6:1. The mean age of presentation is 28.3 years,ith a wide age range (3 to 89 years).AFS has a strong tendency to recur (23.9%) but

arely metastasizes (4.5%). In general, the mortalityate of patients with AFS is quite low (25.4%).

Management of AFS is controversial because ofhe lack of reported cases and experience. In gen-ral, the primary mode of treatment is aggressiveurgical excision with clear margins. Adjuvant ra-iotherapy, at doses such as 50 Gy7 and 60 Gy,12

has been used with no evidence of recurrencewithin the authors’ respective follow-up periods.Nogueira Tde et al13 have used 4,000 Gy to treat aumor that could not be completely resected be-ause of technical limitations, with no evidence ofecurrence after 2 years of observation. Adjuvanthemotherapy has also been used. Combinationherapies—including cocktails of cyclophosph-mide, 5-fluorouracil, and Adriamycin7; cyclophos-

phamide, Adriamycin, and vincristine14; and vin-ristine, cytotoxan, and epirubicin3— have been

used with moderate success. Although some ofthese combinations have been associated with pre-venting tumor recurrence, specific chemotherapyprotocols have yet to be established because of therarity of this tumor.

AFS is diagnosed histologically and is supportedby the clinical information of new-onset rapid en-largement and pain in a longstanding mass. Histo-logically, however, AFS must be differentiated fromAF, ameloblastoma, and fibrosarcoma. AF is charac-terized by benign strands and islands of ameloblas-tomatous epithelium embedded within a fibrousstroma of variable cellularity but without cytologicatypia. Separation from AFS may be difficult espe-cially on incisional biopsy because the sarcomatousmesenchyme may be focal, as was seen in our case.Immunohistochemical studies may facilitate differ-entiation of this lesion because p53, Bcl-2, vimen-tin, and Ki-67 have been shown to be expressedwithin the sarcomatous mesenchyme of AFS.8,10,15-17

Ameloblastoma consists of benign ameloblastoma-tous epithelium embedded within a paucicellularstroma. In ameloblastoma, AF, and AFS, the benignameloblastomatous epithelium showed positive im-munoreactivity for broad-spectrum keratin (AE1/AE3) while maintaining negativity for p53. In addi-tion, overgrowth of the sarcomatous mesenchymein AFS can result in an inconspicuous epithelial

component and may resemble a fibrosarcoma. As

such, adequate sampling is necessary to identify theameloblastomatous epithelium.

In our case, there was a clear demarcation be-tween regions of AF and AFS within the same tu-mor. This supports the transformation hypothesisof AF to AFS as a mechanism of tumorigenesis. Inaddition, it warrants long-term observation of pa-tients with AF. Useful immunohistochemical stud-ies include p53, Bcl-2, and Ki-67 testing, all ofwhich are positive within the atypical fibroblast-like cells of AFS. Although adjuvant chemoradiationhas been used, no clear combination of drugs ordosage of radiation has been prescribed because ofthe lack of experience with this rare tumor.

Acknowledgments

The authors would like to express their gratitude to Dr. T. Daleyand Dr. M. Darling for their contribution to this manuscript.

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