Ameloblastoma

A Symposium

R. LEVY: The ameloblastoma is an epithelia,l tumor, While time will not permit a complete discussion of the derivation and role of the tumor and its supporting stroma, I think that there is time to discuss briefly its essential features. First, let me say that although Kobinsonl has stated, in what he would like us to believe is the definitive paper on the ameloblastoma (that is, that this tumor should be called adnmantoblastonzu), that it is the malignant counterpart of the odontogenic cyst and that it is derived from the outer enamel epit,helium, both the terminology and the discussion 0.f its derivation, as well as its “malignancy,” are certainly still open to further investigation and further discussion. 1 believe that the tumor is an epithelial tumor derived from that portion of the oral ectoderm which has the potential to form the enamel organ. The tumor in the Slye stock strain of mice which Zegarelli” described as adamantohlastoma is probably not a true ameloblastorna as we think of it in terms of human disease. 1 am also one of those who believe that the ameloblastoma is not a malignant tumor. It rarely, if ever, becomes frank carcinoma and it never metastasizes, as we use the word metastasize for other tumors. The role of the stroma in this tumor, I think, is essentially the role of the stroma of any epithelial tumor. This stroma probably is not related to the dental. papilla and therefore is not LLodontogeni~” in origin. Thus, we arc dealing with a tumor which has a great potential for growth, is epithelial in origin, usually begins as a solid tumor, and frequently undergoes cystic degeneration. There is also the question of radiation therapy, but S do not know very much about that. I do wish, however, that we had some figures from somePresented at the annual meeting of the Metrol;olitan-New York Society of Oral Surgeons, Nov. 4, 1953. *Director of Graduate Studies and Research, School of Dental and Oral Surgery, Columbia TJniversity, and Consultant in Oral Pathology. U. S. Naval Hospital, St. Albans, New York. **Chief of Maxi110 Facial Surgery, The Jersey City Medical Center, and Consultant in Oral Surgery, U. S. Naval Hospital, St. Albsns, New York. ***Chief of the Surgical Services and Head of Oncology Division, U. S. Naval Hospital, St. Alba.ns, New York. The opinions and assertions expressed by Commander Grant in this paper are his alone and do not necessarily reflect the official attitude of the TJnited States Navy

mqmrtment.

where as to whether or not these tumors are really radiosensitive. I think that the figures could be obtained from either Sweden or Great Britain. Both countries treat tumors much differently than we do and, according to their staztistics, 1. t,hink 1,ha.t they treat them as well as we do here in America. I should like to know wlmt their findings are. 80 far as therapy is con~crned, for ameloblastomas occurring in the body of the mandible or the lower part of the ascending ramus, I think that the indicated treatment is the minimal section that will include all t.he tumor. The resulting defect can be restored, if necessary, with a,n immediate bone graft, and the patient will have no functional., and little OT 110 cosmetic, deformity. 011 the other ha,&, if I h.ad an amelobla.stoma, myself, which extended above the lower third of the ramus and which, if resect,ed, would cause cosmetic and functional deformity, I would like to take at least one chance with curettage. I might accept resection after the first recurrence: but that might be many years after the curettage. DR. PAI~KER: I am going to attack this problem mostly from the cliniinteresting to me for cal aspect. This subject of ameloblastoma is particularly many reasons. It is one of the tumors that ha.ve been characterized by the pathologists and pa,thologic textbooks as very rare. That, of course, is a matter of opinion. What is rare to one person may not be rare to another. I think that those of us who have worked in the larger teaching institutions have seen many ameloblastomas. The term ameloblastonaa, however, is one of several names that have been given this particular growth. The word ~&~ru~anGama has been applied to it over the years, as well as adamant&e epithelioma. Of course, the differentiation between epithelioms and adamantine epithelioma is not too hard to evaluate, but clinically the tumor is one that is yuite characteristic in many respects. Most ameloblastomas seem to originate in the central portion of the mandible or maxilla. Clinically, of the large group that I have seen personally, about 90 per cent occurred in the mandible and 10 per cent in the maxilla. It is a particularly slow-growing tumor, and most of our cases have started in fair1.y early adult life. It is a tumor that does not seem to develop in the aged. Unfortunately, comparatively few are diagnosed in the very early stages because symptoms are absent. It attracts attention by its growth and concurrent asymmetry of the mandible or ma,xilla due to the expanding perip.hery of the bone. It is generally believed that it develops from the enamel organ and not from the surfa.ce. We find that it occurs at the angle of the jaw more commonly than in other parts of the mandible, and froyn the third molar area, it extends into the ramus, rather than forward with the body of the mandible. Reea.use of the routine use of roentgenograms, we probably pick up a large number of these eases early before they develop sym.ptoms or become clinically evident. The characteristic roentgen appearance in many eases is that of a multilocular cyst. We lmow tha.t it develops from very small areas which many times coalesce, forming one large cystic cavity. In other cases, there may be trebeculae present which give the impression of a multilocular cyst. A fair percentage of easeswe can. diagnose by

1he radiogra.phic

appeara.nct: bee;ntse of this multilocular eharacte~, but 1 think 011 the ra,diograph done. ‘I’hc x-?ay picture is a. guide rind h!S not allow us to make a definite diagnosis. The ame~~)~)~astarna is a benign growth. It is Locally malignant, however, srmeading locally from a center rather than through the lymph or blood ~harr~rel~. In other WOT~S, WI? think of it as a tumor that does not metastasize, :l,lthough there are ca.scs on record that seem to have produced ructastases. On checking up on some of these ca,ses, I find that metastasis to the lungs has been reported a little more frequently tha.n metastasis to lymph uodes. .I think that most of these metastases have occurred aft#ey operation, and I have not found any case in which there was a met,astasis to the lungs noted before the original tumor was detected. Thus, I feel that. marry of these so-called mstxsi-a.sexto the lung have been. aspiration mctastases in which t,urnor cells have been asnitzted arid implanted. into the lung at the time of opera,tion. The growth, as we know, becomes cystic in a large pereenta,ge of the casns and these cysts are quite di-fferent from the odontogenic cpithelial cysts. l‘be latter have a typical cystic fluid with choleatrin crystals, different from t,he cystic Auids that we find in the ameloblastomas, which is often of a gclatiuous character, more yellowish, and not BS clear as that of the cysts that we find in the jaws. A.s a rule, this tumor stays within the cortical portions of the mandible, Occasionally, however, when it remains und&ected for a long period of time, it eventually may absorb some of the cortical bune, perforate it, and involve the surrounding periosteum and muscula.ture. This, however, is not very comn~on. Occasionally we find a disturbance of sensation due to pressure producing anesthesia of the p&s supplied by the sensory nerves. The treatment has been a debat,able subject for many years among oncologists, surgeons, oral surgeons, and pathologists. We know that the tumor is likely to r’ecur unless it is entirely extirpa.tcd, and complete extirpation is very difficult. Those of us who have been doing oral surgery over the Yeats are somewhat inclined to be more conserva,tive in the treatment o-f these tumors than the oncologists working in tumor clinics, who are likely to be very radical. T have observed many of these growths over many years, postoperatively, and Found tha.t as long as the area housing $he tumor growth is kept open or is The minute the excised tumor area sauccrized, we do not have recurrence. closes over entirely, there is a tendency to recurrence. The group at the Memorial Hospital of New York feel that resection o.E the affected bone is essential to the elimination of the disease, but I feel that because t,he tumor is only locally malignant we can, by eonscrvative excision, keep the patient comfortable with a functioning ;jaw over a period of years, although we may have to reoperate several times. However, we see comparatively few cases in which conservative treatment is possible. I have seen several cases in which we have resected a portion of the mandible in which the tumor recurred in the adjacent soft tissues. Also, I have seen a few cases in which resection of the bone beyond the periphery of the disease as seen in the x-.ray picture was not sufficient to stop a recurrence of the growth. Similar cases imy bc formd in the l.iteraturc, \ve

can-not

depend

AMELOBLASTOMA

685

On this basis, I feel that we must try to teach those who are going to do radical. operations that we can maintain that bone, either by immediate bone graft, by splinting, or by maintaining a space between the Cragments, SO that later we can replace the resected part with a bone graft without the very bad cosmetic effects of contracture. I would like to mention at this time a techniqu.e that I have used in a few cases, which I feel is very ;)ractical and which helps to maintain the space that otherwise would be lost by contracture. I take a length of stainless steel wire and contour it roughly to follow the out line of the inferior border of the mandible which is going to be resected. Since this type of tumor is usually confined within the periphery of the boric itself and does not involve soft tissue, we can excise it and still leave a healthy soft-tissue bed. The ends should not be placed into the spongiosa at, the sectioned surfaces because the wire would not maintain the space, as its ends would drill deeper and deeper into the cancellous bone. Ilowever, by making a right angle bend at each end, a flange is provided which prevents this burrowing. This wire holds the space during the healing period (Fig. 1). It can be taken out very readily and replaced with a bone graft. Tn the meantime, you have allowed a bed of soft tissue to be established, into which you can put a bone graft by extraoral means and feel a great deal safer than if you tried to do it intraorally at the time of operation.

b’ig. I.--Drawing’ showing stainless steel pin used to rrraintairl anatomic relatlurlsiup mandibular fragments after segmental resection. The right angle bend at each end of the prevents further burrowing of the pin ends into the cancellous bone.

ot pin

In the maxilla it is Very difticlllt tu cOIktr01 tlic! arrrrlObiil.sl.onlu becttus~ oil the possibility of its spreading -without the confines of the bone. It may extend by contiguity outside the maxilla much more rapidly than it c>xtends outside the periphery of the mandible. Two cases of metsstases to the brain havt: been reported and it seems that those cases, as far as I can find, are contiguous

growths i-4-~atnxmt IYWCZ~

rather with al.thorrgh

than mctast;~scs x-Tay irradiation the tumor is not

through the &c:ulalioxt mn.y retard tbc growth

07’ lymphatics. and prevent

sctrsitive

radiation.

to

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fill. GN.AXT: In forlller times, 2NIlC!lOhl%3t~OiIlZlS WWc lrOta sem c?XWpt ilR -?rl~~aneed cases which required heroic trcatmcnt. Many patients WOE illlOWCd to die from r~osion and extension of tho tumor to the brain and many died from ulceration and infection. ‘\i\‘it;h the advancement in 0li.r niethods Of diagnosis and onr diagnostic abili.ty, thase tumors a,~ being seen enrlicr when they are ctonfinod in the bone. f lawever, despil.e all the ~coont advances in surgery and diagnosis, their treatment will ai ways represent a, difficult probicm for a number of i~casons. One is that surgery in the mandible or the me.xilla may create both a cosmetic and a f~uldional problem. It is a. drastic thing for any patient to have to have a l)ortion of either the maxilla or the mandibic removed. Another aspect of these tumor*s that makes treatment difficult is that they appear in young people. Rpproximatoly 60 or+ 70 per cent of them occur in patients from 1.0 to 3.5 years of age. These people are faced with many years of life and one is, therefore, very reluctant to treat them radically if there is a.ny other way to go about it. Still snothcr aspect of th.cse tumors which makes difficult the proposal of a dcstructivc operation is that t.hcy al’e painless and, therefore, thy involvement of the jaw may be far atlvan~d before more a11cl more arc piokrd up the patient comes for treatment. Iloweve~r, incidental to general. x-rsy examinations of the teeth. This also presents a diffjcnlt problem because ca.rly casts arc usually small acid it is harder to corlvince a patient. that a radical resection is needctl. I woul~l like to point out a striking parallelism in the trcatmcnt of: this disease with one that is very common among general surgical casts, that is, the basal-cell cpithclioma of the skin. The cause of the failure to cure basal-cell epithelioma of the face is penally the same as the cause of the i’ailurc to curt arnolol)last.ont;~s. rlarrlcly, i,hat, -function and. cosmetics a,rc being wcigltcd and bala~~ccd against wide excision of the tumor. There is a general trend t;hrouglrout the country, I believe, away from curettage, and 1 think the ma.in reason for that is that the extent of the If you could open up all the microscopic areas curettage is not broad enough. adjacent to the large cysts and curette and put zinc chloride into them, I am sure that you would have a curative procedure. That would be l.he ideal method, but the problem is that you have no way of knowing where the disease begins and ends. You can rely t.o a larger extent on the x-ray than you can on any other aid, but it is very difficult 1.0 tell if you have gone 1 cm. I~cyontl the tumor, as you started out to do. So you usually begin with a morrtal pict,ure of how much you arc going to seyal)e on the ba.sis of what the rocntgenogram shows. ‘I’his is very inadeq~rai~c. I c tllCrC wer1: some way o-f avoiding that; situation, less radica.l l)rocctlures wo~ltl be sal’c. NOW, if YOU grant that cur&age is inadequate, is thcro a place for a slightly more radical pr*ocedurc? I believe that there is a place, but it certainly is not going to offer itself very often. It is probably the happiest solution that you can arrive at,

if the case will lend itself to it.

P am referring, of COLI~S~,to a. marginal resection. There are a few cases that are suitable for marginal resection. ‘I believe that as long as you can leave the lower margin of the mandible intact you can go free, wide, and handsome on either side of the tumor, leaving an extra margin for safety without difficulty. I feel, however, that most cases will require the next more radical procedure, namely, segmental resection of the mandible. 1 believe that in some cases you co~dd stop short of the articulating head. Although I do not wish to go into any of the details of the surgery, 1 should like to point out that, with the use of an immediate bone graft in SUCK cases, you can get an excellent functional and cosmetic effect. Such cases call for a real combined clinic type of treatment. I would insist on having an oral surgeon see the case, and I would a.lso em.phasize the importance Of the prosthodontist’s giving his advice before anything was done. I do not think a biopsy should be made until the group has seen the patient and come to a decision as to how he will be treated if he has a,meloblastoma. I would also consult a plastic surgeon unless I was doing this type of reparative surgery myself. Biopsy is of great importance in the diagnosis. I come from an institntion, the Zlilemorial Hospital of New York, that favors aslliration biopsy, which 1 find a great help. One should remember that a biopsy can complicate the case to such an extent that the treatment is thereafter conditioned by the very maneuver used to evaluate it. If you can avoid opening into the mouth, you should do it, although many biopsy incisions will heal without becoming infected. In fact, it supposedly has been. one of the diagnostic criteria of amel.obIastoma tha.t it heals rapidly after a biopsy incision, as opposed to ost,eogenic sarcoma or other tumors of that malignant propensity. Restorative procedures to maintain the separation of t,he fragments to avoid contracture should be planned at the time of the operation. The choice of methods depends upon your own experience. You can use metal or bone. Probably you should not use bone if you have operated through the mouth, although even these patien.ts do quite well. It is dificult to lay down rules which will apply in every case. The important thing is that the procedure should be well planned in advance and the repair of deformity evaluated beIore surgery, and not after the defect ha,s been crea.ted. Dr. Parker has raised the question of difference in treatment of ameloblnstorna of the mandible and of the maxilla. I feel that the treatment is the same. The problem is exactly the same, so far as getting rid of the tumor is concerned, and that is a wide local excision. If you can d.o it with a pa-rtial resection of the maxilla, fine. If it takes a complete resection, it should be done and the pa.tient probably will miss his maxilla considerably less than he would. miss a good portion of the mandible. Certainly he will be rehabilita,ted more quickly with a maxillary resection tha.n he would be -with a mandibular resection. I think that Dr. J?a~*kcr’s wire device illustrates as well as anything else the value of this combined group or consultation business. That to me, is the answer which I have been seeking for a long time without ever quite

seeing. It is so simple it is almost in any surgeon's hand. If trothing else, I am delighted. to have picked up this thing because it, is so uaiversal1.y applimble. Now, everybody has a pet trick on resloration and it is almost a waste of time to go into all of them. Dr, Parker did point out tha,t, there are failures and that is the thing 1.would like to emphasize. Do not I.& one case report of a ,suceessthrow you. Again, that is the value of an experienced group, rather than one man running to the literature and finding a method of treatment for amel.oblastoma. Let him get a group opinion of people who have seen failures as well as SUCC~SS~A by all meth.ods, and, believe me, everybody who has treated ameloblastoma in any numbers has had failures with any method, radical or conservative. Reforc I get into more detail, I would like to think that 111.. Parker who spoke for conservatism is probably a little more radical than he says. He has a gadget there with which he can filr up a patient wit,h free handling ; 1 may be wrong, but I think that he will do a segmental resection of the mandible when the proper case comes along and T do not think he is SO much at variance -with me, really. In other words, I think we are pretty much agsod. .1‘differ with Dr. Levy in regard to radiosensitivity. I think YOU should a.pproach an opinion on the basis of the fact that the ameloblastomas actually aSriseout of the basal-cell layer o-f the epithelium. T alluded earlier to the striking parallelism between the clinical course of arnelohlastoma and that of basal-cell carcinoma. These tumors arise from the basal-cell layer and, indeed, used to Others have called them adamanbc called inZrnosseous basakcsU e&he&ma. t& epil-haliomns. Having arisen from. that source, you might expect to find the same radiosensitivity as in basal-cell carcinoma. Basal-cell carcinomas are radiosensitive but they are not particularly so. They take anywhere from 3,000 to 5,000 r. to cure. llowevcr, radio-ostconeerosis i,akes place at about 5,000 to 5,500 r., and with 6,000 r. you can probably necrose any bone in the body. There is some difference in the type of radiation used. Low voltage is more nccrosing than high voltage, but 4,500 r, is very close to the osteoneorosislevel. Therefore, 1 am dubious of the value of radiation in this disease. I know that it is too risky so far as I am concerned. Finally, I should like to repeat what T said before: I think that any recurrcnc.c is a failure. It is true that some patients have gone along and have becu comfortable and retained their mandibles after curettage. IIowever, if you weigh that against the effectiveness of a primary excision with a replacement that functions well, and permanent freedom from disease and freedom from worry about recurrence, I think that resection offers the paGent the better prognosis. I know that curettage has been fairly common in the past and perhaps it is never going to be discarded compld.cly, but I think that modern methods have made it obsolete. Formerly, it was necessary to think of conservative operation, whether recurrence occurred or not, as more radical surgery a.ud bone grafting presented too great a risk of infection and even death. Today you can -perform surgery without a high murt,alit.y rate. I think that you should be thinking seriously about doing something a little more definitive if possible.

The unfortunate thing is tha.t nobody has enough eases to prove this. Recurrences arc so long in coming that no one has accumulated a large enough series. If I could look you right in the eye and gua.rantee cures with complete segmental resection of the mandible, I would be even more dogmatic. This treatment has not been practiced long enough to offer a guarantee that such cases will not follow a course something like the curetted ones. However, on the basis of good surgical principles and basic science and the advancement of the art of surgery, I think that the time has come when we should be more radical. Recurrences are failures, regardless of whether or not they take fifteen years to recur. Every recurrence subjects the patient to real. danger of metastasis or extensive recurrence which cannot be cured locally. Reference 1. Robinson,

Marsh:

hdamantoblastoma; California .D. A. 19: 16-27, 1951. 2. Zcgarelli, Edward : Adamantoblastomas 23, 1944.

the in

lrnportance the

Slye

of Stock

Early of

Mice,

Diagnosis, Am.

J. J.

Path.

South. 20: