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Cases Series
Histopathologic fe ature s and manage me nt
of ame loblastoma: study of 20 case s
Head and Neck, Stomatology and Pathology Services of Hospital Heliópolis, São Paulo, Brazil
Rui Henriques Martins Josias de Andrade Sobrinho Abrão Rapoport Marilene Paladino RosaINTRODUCTION
O do nto g enic amelo blasto ma (O A) o f the jaws is a rare neo plasia o f the o ral cavity (0 .7 8 %) with a 5 :1 mandible/ maxilla relatio n, with the mo lar regio n and the ascendant ramus being the mo st affected areas. Co mparing o ur results with the literature demo nstrated to us that this tumo r may be co nsidered to be a wo rldwide pro blem due to the similarity in clinical finding s amo ng diffe re nt e thnic g ro ups. The wide ning o f o ur kno wledge will allo w us to find so lutio ns and fight against the o verall harmful effects o f such tumo rs.
The cho ice o f best manag ement metho d ne e d s to b e ma d e b e tw e e n a histo lo g ic a l classificatio n into types 1 , 2 and 3 (Vickers and G o rlin),1 o r by establishing the relatio n between clinical behavio r and histo patho lo g ical pattern according to age and anatomical location (Regeze, Kerr and Courtney).2 After a histopathologic review, we thus established a co rrelatio n between these features and the best therapeutic pro cedure, with the aim o f decreasing disease recurrence.
CASE SERIES
Between 1 9 8 0 and 1 9 9 7 , 4 5 o do nto g enic tumo rs were reviewed, representing 0 .7 8 % o f
ABSTRACT
Ba ck ground: O do nto g enic amelo blasto ma (O A) o f the jaws is a rare neo plasia o f the o ral cavity (0 .7 8 %) with a 5 :1 mandible/ maxilla relatio n, with the mo lar reg io n and the ascendant ramus being the mo st affected areas. Co mparing o ur results with the literature demo nstrated to us that this tumo r may be co nsidered to be a wo rldwide pro blem due to the similarity in clinical finding s amo ng different ethnic g ro ups
Ca se series: The purpo se o f this study o f 2 0 patients with amelo blasto ma o f the mandible and maxilla diag no sed at the Sto mato lo g y and Head and N eck Services o f Helió po lis Ho spital, São Paulo , Brazil, fro m 1 9 8 0 to 1 9 9 7 , was to establish the histo patho lo g ic pattern o f classificatio n o f tho se tumo rs thro ug h o ptical micro sco py and the relatio n o f this histo patho lo g y to therapeutic manag ement. Using the Reg eze, Kerr and Co urtney classificatio n (1 9 7 8 ), we diag no sed fo llicular tumo r in 1 1 cases, plexifo rm in 6 cases and unicystic in 3 cases, and perfo rmed surg ical resectio n with a safety marg in o f 1 .5 to 3 .0 cm in the fo llicular and plexifo rm cases and bo ne curettag e in the unicystic cases.
Keyw ords: Amelo blasto ma. Histo patho lo g y. Surg ery.
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all o ral cavity benig n tumo rs (Table 1 ).
A selectio n o f 2 9 amelo blasto ma cases was made fro m amo ng 4 5 patients with o do nto g enic tumo rs (Ta b le 1 ) who ha d b een sub mitted to different surg ical pro cedures at the Sto mato lo g y a nd He a d a nd N e c k Se rvic e o f He lió p o lis Ho spital between 1 9 8 0 and 1 9 9 7 . Fro m this selectio n, 2 0 cases were reviewed by means o f histo p a tho lo g ic sp e c ime ns, using o p tic a l micro sco py with hemato xylin-eo sin, relating them to a g e , se x, e thnic g ro up a nd surg e ry. Fo r statistical analysis, the hypo thesis test was used fo r relating the results fro m o ur g ro up to tho se in the literature.
Amo ng these cases, the lo catio n affected was the mandible in 2 7 cases and the maxilla in 2 cases, who se ages ranged fro m 2 0 to 3 0 years o ld, co mprising 1 6 blacks and 1 3 whites, 1 4 females and 1 5 males. Reanalysis was po ssible in 2 0 cases, which were classified acco rding to the Regeze, Kerr and Co urtney2 criteria (Table 2 ).
Ta b le 2 sho w s tha t the re w a s a predo minance o f white patients o ver black o nes: two -thirds o f all cases, summing the three types o f tumo r. The male to female ratio was 7 :4 fo r the fo llic ula r typ e . The ma nd ib le lo c a tio n o ccurred in 1 9 cases whereas there was o nly 1 in the ma xilla lo c a tio n. The histo p a tho lo g ic re c la ssific a tio n sho w e d tha t fo llic ula r
amelo blasto ma (1 1 cases) affected the bo dy o f the mandible in 6 cases, the ascendant ramus in 3 c a se s a nd the a ng le in 2 c a se s. Fo r the plexifo rm type, there were 5 cases in the bo dy o f the mandible and 1 in the ang le, and fo r the unicystic type, 2 in the bo dy and 1 in ang le (Fig ures 1 , 2 and 3 ).
The d istrib utio n o f a me lo b la sto ma histo lo g ical type acco rding to ag e is sho wn in Table 3 .
DISCUSSION
G ünhan et al3 no ticed a rate o f 1 .3 % fo r o do nto g enic tumo rs o f the o ral cavity, o f which 4 6 .3 4 % were amelo blasto mas. In o ur results, the ra tio o f these tumo rs wa s 0 .7 8 % to 6 4 .4 4 % (Table 1 ). N o predo minance o f o ne sex o ver the o ther was sho wn in o ur data (Table 2 ), no r has it been o bserved by o thers. The predo minant ag e g ro up in o ur material was 2 0 to 3 0 years o ld (Table 3 ), whereas o ther series sho wed a wider rang e o f 1 1 to 3 1 years o ld. The frequency o f the fo llicular type was similar fo r all ag es fro m 1 1 to 6 0 years o ld, with an averag e o f 4 5 .1 years o ld. Fo r the o ther two categ o ries (plexifo rm and unicystic), g reatest incidence o ccurred within the a g e ra ng e 1 1 to 3 0 yea rs o ld, with the averag e ag es being 3 4 .3 and 2 2 .7 years o ld, respectively.
The fo llicular type o f amelo blasto ma was the mo st co mmo n (Table 3 ), ag reeing with the finding s o f Reg eze et al.2 Acco rding to Chapple and Mano g ue,4 this tumo r co nsists o f discrete fo llicles with a similarity to the starry reticulum o f the external enamel with a varying quantity o f co njunctive tissue stro ma. The co vering epithelium is c o lumna r o r c ub o id with nuc lei po sitio ned
Ta ble 1 - Rela tion betw een odontogenic tumors a nd a melobla stoma
O do nto g enic Tumo r N umber %
Amelo blasto ma 2 9 6 4 .4 4
O thers 1 6 3 5 .5 6
Tota l 4 5 1 0 0 .0 0
Ta ble 2 - Distribution of Amelobla stoma histopa thologica l types a ccording to sk in color, sex a nd loca tion
Histo patho lo g y N umber Skin co lo r Sex Lo catio n
Black W hite Female Male Mandible Maxilla
Fo llicular 1 1 4 7 4 7 1 0 1
Plexifo rm 6 1 5 4 2 6 0
Unicystic 3 1 2 1 2 3 0
Tota l 2 0 6 1 4 9 1 1 1 9 1
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o ppo site the basal membrane. In Fig ure 2 , the plexifo rm type is sho wn to have deg eneratio n o f the stro ma with the fo rmatio n o f cysts with few areas similar to the starry reticulum, thus justifying its lo w ag g ressiveness.
Ac c o rding to Va sa n,5 the fo llic ula r type co nsists o f discrete epithelial lines in a co njunctive tissue stro ma a nd the plexifo rm c o nsists o f a c o ntinuo us line o f a na sto mo sis. Ac c o rding to Ackerman, Altini and Shear,6 the unicystic type is fo und a s thre e fo rms: unilo c ula r c a psule s, diffused intra lumina l a nd diffused intra mura l, spreading o ut to the middle o f the co njunctive tissue. This has been co rro bo rated in the new classificatio n fro m Philipsen and Reichart.7 In o ur ma te ria l, the g re a te st inc id e nc e w a s o f the fo llicular type (1 1 cases), co mpared to plexifo rm6 and unicystic,3 with 1 9 cases o ccurring in the mandible lo catio n and 1 in the maxilla.
The a na to mo pa tho lo g ic a l c la ssific a tio n o f the a me lo b la sto ma is no t ye t ro utine , b ut we a re c o nvinc e d tha t de a ling with the differe nc e s in histo lo g ic pa tte rns is re le va nt in e sta b lishing surg ic a l pro c e dure s, fro m the simple st b io psies a nd b o ne sc ra ping to the mo st inva sive a c ts. Ac c o rding to W illia ms,8 the the ra pe utic mo de l a nd tre a tme nt o f the se tumo rs de pe nds o n the ir siz e. The c ho ic e o f extra - o r intra -o ra l a ppro a c h is de te rmine d during surg ic a l pla nning , with
Sao Paulo Med J/Rev Paul Med 1999; 117(4):171-4.
Figure 1 - Photomicrograph of follicular ameloblas-toma (hematoxylin eosin x250). 1: islets or trabeculae formed by cells loosely arranged like the starry reticu-lum of the external enamel. 2: layer of high coreticu-lumnar cells reminiscent of ameloblasts, with nuclei positioned opposite the basal membrane. 3: follicles.
Figure 2 - Photomicrograph of plexiform
ameloblas-toma (hematoxylin eosine x250). 1: interconnected epithelial bridges. 2: degeneration of the stroma with cyst formation. There are minimal areas of starry reticulum and in some regions ameloblasts are not evident. No inflammation in the stroma.
Figure 3 - Photomicrograph of unicystic
ameloblas-toma (hematoxylin eosin x250). 1: cysts in the pro-cess of formation. 2: conjunctive tissue dispersed over the stroma.
Ta ble 3 - Amelobla stoma histologica l type rela ted to a ge ra nges
Histological type
Ag e Fo llicular Plexifo rm Unicystic To tal
1 1 || 2 0 2 1 1 4
2 1 || 3 0 2 2 2 6
3 1 || 4 0 2 1 0 3
4 1 || 5 0 2 1 0 3
5 1 || 6 0 2 1 0 1
6 1 || 7 0 1 0 0 1
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Sao Paulo Med J/Rev Paul Med 1999; 117(4):171-4.
the a im o f c o mple te ly e xtirpa ting the tumo r, w ith o r w itho ut re c o nstruc tio n o f the b o ne a ffe c te d. The ra py is no t the ma in fo c us o f this pa pe r, b ut whe n re se c tio n is e sse ntia l, b o ne rec o nstruc tio n using pla tes a nd tita nium sc rews o r a n inte g ra te d b o ne impla nt ma y b e c o me ne c e ssa ry.
It can be seen that the invasive bo rders o f a me lo b la sto ma s a re diffuse a nd the c linic a l co ncept o f a safety marg in is needed. In o rder to prevent recurrence, we wo uld sug g est a safety marg in o f 1 .5 to 3 .0 centimeters. N evertheless, Fe inb e rg a nd Ste inb e rg9 ind ic a te d iffe re nt surg ical marg ins fo r resectio ns depending o n the a na to mic a l lo c a tio n a nd e sthe tic invo lve me nt. A c c o rd ing to Li, Fa b ia n a nd G o o dman,1 0 surg ery is the o nly treatment fo r a me lo b la sto ma , d ue to its re sista nc e to irra dia tio n the ra py. Ana sta sso v e t a l1 1 ha ve repo rted that radio therapy alo ne o r asso ciated with chemo therapy is o nly indicated fo r patients o f advanced ag e.
Fina lly, w e b e lie ve tha t histo lo g ic a l c la ssific a tio n o f a me lo b la sto ma w ill b e c o me ro utine in the ir mo rp ho lo g ic a l c ha ra c te riz a tio n. Re g ula r us e o f immuno histo c he mic a l p ro c e d ure s w ill in the future b ring mo re re lia b le re s ults fo r d e te rmining b e st surg ic a l p ro c e d ure s fo r p re ve nting re c urre nc e o f suc h tumo rs. Fo r the p le x ifo rm a nd fo llic ula r ty p e s, ra d ic a l re se c tio n is the b e st p ro c e d ure , w ith a sa fe ty ma rg in o f 1 .5 to 3 .0 c e ntime te rs, a nd fo r the unic ystic typ e , b o ne c ure tta g e is ind ic a te d .
RESUMO
Contex to: O amelo blasto ma o do nto g ênico é uma neo plasia rara da cavidade o ral (0 ,7 8 %), co m relação de 5 :1 entre a lo calização na mandíbula e na maxila, sendo as reg iõ es mo lar e do ramo ascendente as áreas mais afetadas. A co mparação entre no sso s resultado s e a literatura permite-no s co nsiderar esta neo plasia um pro blema mundial em função do s achado s clínico s semelhantes em diferentes g rupo s étnico s. Rela to de Ca so: A pro po sta deste estudo co m 2 0 pacientes co m amelo blasto ma da mandíbula e da maxila, diag no sticado s no s Serviço s de Esto mato lo g ias e Cabeça e Pesco ço do Ho spital Helió po lis, São Paulo , Brasil, de 1 9 8 0 a 1 9 9 7 , é estabelecer o mo delo histo pato ló g ico de classificação destas neo plasias através da micro sco pia ó ptica e sua relação co m a co nduta terapêutica. De aco rdo co m a classificação de Reg eze, Kerr e Co urtney (1 9 7 8 ), fo ram diag no sticado s o tipo fo licular (1 1 caso s) o plexifo rme (6 caso s) e o unicístico (3 caso s). A indicação terapêutica fo i ressecção co m marg em de seg urança de 1 ,5 a 3 ,0 cm para o s do is primeiro s e curetag em para o tipo unicístico .
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Rui Henriques M a rtins - Bucco -Maxillo -Facial Surg eo n
Josia s de Andra de Sobrinho - Head and Neck Surgeo n
Abrã o Ra poport - Head and N eck Surg eo n
M a rilene Pa la dino Rosa s - Patho lo g ist
Sources of Funding: N o t declared
Conflict of interest: N o t declared
La st received: 2 5 February 1 9 9 9
Accepted: 1 March 1 9 9 9
Address for correspondence:
Abrão Rapo po rt Helió po lis Ho spital
