Removal of Large Ameloblastoma of Mandible

Author: UMichDent

Welcome to the University of Michigan Dentistry podcast series promoting oral health care worldwide. Today we would like to take the opportunity to present some of the preoperative considerations in a patient of ours who has been kind enough to agree to the recording of some of the sessions relating to her tumor. She has a rather interesting condition and weíll ask her about it. Mrs. Brooks is 50 years of age and she came to us first in the oral surgery clinic about a year and a half ago and what was your reason for coming in at that time, Mrs.

Brooks? Mrs. Brooks: At the time, Dr. I had, I had discovered this swelling on my side here and I was curious about it naturally so I thought Iíd come to this place. And I came here and they started treating me. Dr. Hayward: It was just swelling but no pain? Mrs. Brooks: No, no pain at all.

Dr. Hayward: And where was that specifically on your jaw? Where was it swollen? Mrs. Brooks: From the lowerÖ side here. On my left side. Dr. Hayward: Well then at that time then a procedure was carried out for you, was it not? Mrs. Brooks: Yes it was. Dr.

Hayward: And did you have much trouble after that was done? Mrs. Brooks: No trouble at all. Dr. Hayward: According to the records at the hospital, Mrs.

Removal of Large Ameloblastoma of Mandible

Brooks had a lesion that we will see radiographically in a few moments which was removed a year and a half ago and were -- or two and a half years ago actually and was diagnosed as a cyst of the jaws. And she was seen post-operatively only once, it was suggested that she come back but she didnít come back. Was there any special reason why you didnít return? You were just feeling alright or what was the trouble? Mrs. Brooks: I was feeling good but I didnít want to think, or I wanted to pretend like it wasnít there.

I didnít want to face up to facts. Dr. Hayward: Trying to dismiss it from your mind. Mrs. Brooks: Thatís right. Dr.

Hayward: Well then, again, you started to have some swelling down there. Mrs. Brooks: Right. Dr. Hayward: About how long ago was that? Mrs. Brooks: HmmmÖ well I guess really it never really did go away.

It was there all the time. UmÖ I began to get in my mind that I should go back and have it corrected so I decided to come back. Dr. Hayward: Weíll have a look in Mrs. Brooks mouth in just a moment. Before we do, however, you may have observed that in the midline of her upper lip she has a very inconspicuous but nevertheless evident scar and that is from a condition at which forward she was also treated for at the medical center.

That was a swelling of your upper lip? Mrs. Brooks: Thatís right. Swelling.

Dr. Hayward: Uh-huh. And did that change much, did it go up and down? Mrs. Brooks: No just one spot. It stayed in one place. Dr. Hayward: Uh-huh and was it soft or hard? Mrs. Brooks: Soft.

Dr. Hayward: Uh-huh. The records at the hospital indicate that Mrs. Brooks had a hemangioma of her upper lip, a localized lesion. Had you had that for a long time? Mrs.

Brooks: Quite a while. Dr. Hayward: Uh-huh. Perhaps when did you first notice that upper lip lesion? Mrs. Brooks: Oh, maybe six years ago. Dr. Hayward: Uh-huh.

Well, at any rate that was the diagnosis and that has been removed completely and has not recurred. We will look at the anterior part of Mrs. Brookís mouth and Iíll ask you to try to put your head slightly forward, and now back against the headrest and weíll put in these retractors. If you can open please. And then close. Bite together.

Now as we come in on Mrs. Brookís mouth youíll see sheís partially dentureless. The area in our immediate concern has been biopsied ten days ago and therefore a defect is seen in the gingival region to the left of the midline. Letís try to put your chin down just a little farther. Now we can come in close and have a greater impression of the swelling that is here. This is sort of a crater-like defect. The crater has been produced in the zone of the biopsy.

There was a preliminary aspiration of this lesion with a needle which yielded some scant amount of fluid and that was followed by the biopsy. If we would palpate this area, weíd find that it is really quite firm to our palpating finger. Now there is considerable resistance here throughout. It is not soft.

And it is not painful. Thatís not hurting you when I push on it, is it Mrs. Brooks? Mrs. Brooks: [Shakes head] Dr. Hayward: Okay. So weíll come back in a moment to have a look further at what may be indicated for that lesion but now weíll look at the radiographs taken two and a half years ago first and then the current series. We see a Panorex view here which was taken in January 1972 at the time Mrs.

Brooks first appeared and we would see the configuration here of the mandible and if we look at the outlines of the inferior alveolar nerves bilaterally we see as we come toward the symphysis area that there is a peculiar radiolucency. We will see that peculiar radiolucency that was associated with some expansion. According to the records at that time, aspiration again was followed by intervention and a cavity was encountered and from the cavity, a lining, a cystic lining was removed. We will review the histopathology of that lesion a little later.

At any rate, it was diagnosed as a cyst and it was diagnosed as a non-odontic cyst. This would be some type of inclusion perhaps a mid-mandibular cyst or primordial cyst or rare entity to be sure. Mrs. Brooks was asked to return, her immediate follow-up course was satisfactory and as you have heard from her she did not come back and did not have an opportunity for us to monitor this region. So we did not see her until this visit and at this time you will see in the lower Panorex a very extensive lesion. We see what might be best described as multiloculation in the destruction of the mandible. The Panorex views of course are blurred in the midlines and youíll have to compensate for that with me as we look at some of the details here this has a multiloculated or rather soap bubble appearance and it extends back into the body of the mandible and it goes nearly from first molar region around to the other first molar area.

That is what appears in this set of films. Weíll now look at the occlusal views. Turning then to the occlusal view, we see the teeth in the area slightly displaced by this process. These are the films of two and a half years ago. And one can see a rather irregular radiolucency here that is somewhat expands isle and if we turn to a different projection on an occlusal film, it gives us the outer cortex, weíll find an even more interesting, delicate, expansion out here suggesting that a process has ballooned this out. It is interesting that the operator two years ago was able to identify and to eliminate from this area a discrete cyst lining. If we now come to our films of today, we would see that after two and a half years, the process is far more extensive.

It has expanded and as we look at another occlusal view finally this one on the right, we would see a greatly expanded mass. The jaw being literally over twice its normal width and there are several important areas to look at in detail. The genial tubercles are here. As we follow the lingual cortex that we will be hoping to conserve as we'll talk about surgery later, weíll see that there is one point right here where it is very close in that particular projection. We have the hope that that is a relatively small area in diameter and that there may still be some continuity of lingual cortex across that position.

At any rate, we deal here with moduloculation and as moduloculation goes, this could be one of many things, many types of tumor. The obvious and important one to think about is ameloblastoma and that is the diagnosis that was given on the biopsy taken last week. There are a variety of ameloblastomas. This seems to be the classical form. Soap bubble lesions can also of course bring to mind a number of different changes. The possibilities of hemangioma, the possibilities of fiber osseous disease, fibrous dysplasia, the possibilities of other problems of histiocytosis might be considered and certainly other forms of neoplasm both benign and malignant and both primary and metastatic has to be considered in these situations.

But we go back to the patient with radiographic evidence that we have an expanding lesion which has changed but two and a half years is quite an interval for the relatively slow process that has gone on. Weíll come back now then to Mrs. Brooks and weíll reaffirm some of our clinical impressions. Now Mrs. Brooks you donít have any numbness in your teeth or your lower lip? Mrs. Brooks: Not at all. Dr.

Hayward: They feel perfectly normal to you. Mrs. Brooks: Very much so. Dr. Hayward: Uh-huh. And the displacement of teeth, you havenít been aware of any particular change in the position of your teeth or your bite? Mrs. Brooks: No. Dr.

Hayward: Okay. Well Iíd like to point out just in closing the size of the tumor. We can see if I look at her chin and feel it here that it expanded rather markedly from the point between my two thumbs. Thereís a marked expansion here that is very firm, hard, painless. There has been no deficit in motor function here she has complete control of her lower lip. So there are not neurological deficits either sensory or motor. Now weíll have these retractors in again.

Now would you close again please? We have already demonstratedó And would you drop your chin down a little? Thatís fine. Now Iíd like to have you open your mouth widely. We will anticipate the need, on the basis of radiographic and clinical boundaries, to go back to the first molar areas bilaterally and all of these anterior teeth must be removed with the tumor. Weíll attempt to leave the lingual cortext of bone and the lingual periosteum and we will then try toónow if youíll close again pleaseówe must of course excise all of the area where the ameloblastoma has penetrated the gingiva. When the ameloblastoma penetrates soft tissue they tend to be far more aggressive than their characteristics while they are in bone.

So we will hope post-operatively to have Mrs. Brooks back with us after we have removed this tumor from her mandible. We have the opportunity to follow the course of Mrs. Brooks whom you saw in a pre-operative sequence. Mrs. Brooks you were operated on about six days ago? Mrs.

Brooks: Right. Six days ago. Dr. Hayward: And it will be a week tomorrow, right? Mrs. Brooks: Right. Dr. Hayward: And are you having very much pain? Mrs.

Brooks: No, I havenít. Dr.Hayward: Mrs. Brooks has an intraoral approach for her large ameloblastoma of the mandible and her tumor was resected in a manner that we will review. I think perhaps a return to the initial radiographs and immediate post-op radiograph will be somewhat helpful for that. Weíll come back to her in a moment. As we look at these radiographs, youíll recall that the upper film shows us multiloculated destruction of the bone which in this irregular appearance had expanded and had gone back behind the levels of the metal foramina bilaterally. So if we look down at the post-operative film, we see an appliance in place. Weíll look at this intraorally in just a moment.

It is a cast metal appliance and it locks into her remaining molars. The tumor has been resected along these lines of cut. The approach was made be a full de-gloving of the entire mandible and an excision of the overlaying gingiva and some details of that weíll try to show with some slides. We are reminded in this pre-operative photograph of Mrs.

Brooks that the tumor of her anterior mandible had generated a fair prominence here of the lower lip as compared with the upper lip and we will go through a series of photographs of the stages of the surgery when Mrs. Brooks was in the operating room under nasal endotrachael general anesthesia. This represents what is commonly known as the degloving procedure in that the lower lip is literally degloved from anterior mandibular surface. If we look back here, weíll see the metal nerve on the right, uninvolved side and the exposure that is made back here the inclusion of the alveolar attached gingival particularly in the soft tissue out here thatís been overriding the tumor. This represents the musculature of the lip where the sharp dissection was carried out to leave a border of normal tissue away from the prominent expansion of the bony tumor mass.

So this is degloved and was approached from both an anterior approach and then the dissection was carried down further toward the inferior border. With the dissection carried down further, toward the inferior border, the lateral saw cuts have been made with the striker saw. These go through to the lingual plate, through the lateral or buccal plate, through the medullary bone, and spare or leave the cortical bone of the lingual plate with an adequate tumor margin here to account for the possibilities of some invasion beyond what were the clinical boundaries. A similar cut has been made over here and we then will be ready to expose the inferior border. Here were the more extensive degloving with the retraction of the lip and chin down, we see the inferior border of the mandible where it has been cut in order to leave just the lingual plate. You recognize the attachment here of the anterior belly of the digastric muscle. This osteotome then is going in to complete the section.

A cut similar to this was made on the lingual side of the alveolar crest so that the tumor mass here is being lifted away leaving only the lingual rim of the mandible. In the surgical specimen we see the block of mandible that represents all of the anterior mandible from molar to molar region. We see the mental foramen on this side and the millimeter scale on this knife handle to indicate the relative size, the attached gingiva here, the overlaying soft tissue that was removed. Weíll now turn the specimen over and see the other side. This represents the inner surface and under surface of the specimen and we can see the type of tumor destruction that is present here. Each of these little caverns that is honeycombed represents a mass of tumor cells that has destroyed the bone and generated some soft tissue fibrosis around and expanded the entire contour of the jaw. We see at the margin normal bone down here and the beginning of tumor at this particular point.

So it was within the confines of cortical bone except in the big mass here where the overlaying soft tissues were taken. Now weíll see the residual mandible. Although this might appear to be the outer cortical table of bone, it is not.

It represents the lingual table or cortical plate that has been smoothed out by surface mechanical debridement with an Antrim bur in order to eliminate any possible caverns of tumor. We can see here this would represent the cross-section of the mandible from the outer cortex here into the inner cortex. At this particular place the tumor seemed to be particularly invasive and threatened to penetrate the bone at that point. For that reason, this opening was made in order to assure ourselves that we had eliminated bone that was involved by any gross tumor and then the soft tissue bed was removed from this periosteal region in order to be sure that we had obtained a complete peripheral excision of the tumor. That on microscopic study came back as tumor-free as did the margins of bone and soft tissue. One can see the residual alveoli of the incisors up here just a lingual plate of the alveolus. And then this thin bone, the bone is very thin here, is of course vulnerable to fracture.

So the mandible needs support in order to avoid that vulnerability of fracture. This represents a stage in healing to illustrate the type of mechanical support that was afforded by the appliance that was wired to the molar teeth. It spans and reinforces this thin lingual cortex in order to prevent any fracture during the initial phases of healing. From the adhesion here, we have in mind the place where the major soft tissue deficit occurred at the time of surgery when all of the overlying gingiva and the overlying muscle of the lip was excised in this vulnerable region of maximal expansion. This is the photomicrograph of the surgerical specimen. It was removed for Mrs. Brooks and we can see initially under this magnification the characteristic nest of cells that represent the primitive ameloblast. We see the contouring here of these palisaded cells that sort of dip in and invaginate sort of like the dental lamina might do and then the cystic areas that are here and around and as we look down in here under highest magnification we can the tendency for the cells to be arranged in a palisaded form of classical ameloblasts.

Now this tumor and this nest of tumors had elicited quite a fibrous reaction around them as we go back out and we can see the tissues into which this had been invading. We see over here the bone margin. This is a trabeculae of bone representing a portion of the bone into which this tumor was invading when we see the close proximity of tumor cells to it and other sections showed the tumor well within these and you see the general fibrotic or desmoplastic response to the nest of tumor. And if we go from the bone of the jaw outward toward the skin, we would see over here a proximity to muscle. This is the striated muscle of the lower lip that was removed along with the soft tissue and the overriding mucosa from that large mass that you may recall.

So we have here a classical ameloblatoma and one that has all of the characteristics of that unique epithelial neoplasm. But as we look at this post-op film now we see the margins at which the resection was made and at one point there was this penetration through the lingual plate. That penetration was very small and we enlarged it to about four times the original aperture in order to be sure that we had eliminated all of the involved bone margin and so we could get good samples of the soft tissues that were through the lingual plate. Those were reported as being free of tumor. So we have a situation where the mandible, weakened by the resection of about seven-eights of the cross-section diameter of the mandible at this point with only a thin lingual plate holding it together.

Uh, pathologic fracture or accidental fracture is being avoided by the support which this metallic splint lends to the weakened mandible. Now it may be somewhat difficult as we return to Mrs. Brooks to demonstrate completely the post-operative situation but weíll try to do that and uhÖ Annie I wonder if we can have your chin down just a little bit I think thatíll help. And now close your lips together. And you can see she has full competence of her lower lip.

And weíll have a look inside. Iíll try to slide this cheek retractor in here. Now would you close a little bit Annie? Letís see. Now try to close. Uh, drop your chin again. Okay, well youíre getting quite a reasonable view of the suture line of the appliance locked around this molar back here. And the sutures that were just put in last week. She has a slight midline dehiscence of the incision which is of no great consequence.

Itís granulating in and she was put on an antibiotic program. Now close your jaws together. You can see now that she has functional contact of the molars. And just stick your tongue out. Full range of motion of tongue.

Now you can put it back. Again close together. Obviously she has numbness of her lower lip and chin out here. These metal nerves were divided and the canal contents were taken along with the tumor mass. So Mrs.

Brooks is a little bit limited on her dietary intake. Weíre going to leave that appliance in place for at least two months. Sheíll get on to handling the cleaning of the appliance a little better as she get more soft tissue healing. Weíre continuing in our interest in the follow-up of our patient Mrs. Brooks.

It has now been six weeks since the rather extensive operation on her mandible for the removal of an ameloblastoma. And we would just like to check with her on how she is getting along. Are you having much pain, Mrs.

Brooks? Mrs. Brooks: I havenít had any pain at all. Dr. Hayward: No pain. And youíve been eating? Mrs. Brooks: Very much so. Dr. Hayward: And uh, the appliance that weíre going to take out of your mouth today thatís been fairly comfortable too? Mrs.

Brooks: Well sometimes, when Iíve thought about it I guess gets a little uncomfortable. Dr. Hayward: Uh-huh.

Well we would have a look inside Mrs. Brooks mouth to recall the subtraction that was made. Later on weíll have a look at her chin in profile you may recall her chin was very prominent with the tumor. Now try to close a little Mrs. Brooks.

Thatís good. Try to close a little more. Thatís it. So when we come in would you just try to lower your chin a little bit please. Thatís good. Very good.

So one sees the appliance that has been used really to support the jaw and to protect the residual thin lingual plate from fracture during these six weeks of healing. The soft tissue healing is very complete as you can see. Are your molar teeth together? Try to bite all the way down. Now with that contact in the back sheís been functioning. The future restructuring considerations are a little far off.

Right now weíve been interested in making sure that clinically and radiographically she is free of tumor. Right now try to open again a little bit. And I wonder if you would just try to slip that appliance out. Would you try to remove it for me? While weíre showing it off here.

It may be a little bit difficult. I can flip it off for you. You hang onto that retractor on your side there. That a girl.

This hasówas previously secured by wiring and has a little clasp on it. Iím going to have some interesting problems. So you can see the type of appliance that was there. These clasps fit on the molars and this has provided good stability during the time that she has been in fixation. Now weíll have a little better look perhaps at the residual ridge. We can see how prominent it is. And certainly itís not the normal configuration of a ridge.

Thereís an undercut in part but in general the quality of the tissue is quite good. The adhesion that's more on the left side was of course where the overlaying soft tissue was completely removed. Now would close your jaws together again Annie all the way down. Just try to bite together. Thatís fine. Now we can see this molar is in complete function. And eventually weíll be concerned about the possibilities of tolerance of appliance over this residual ridge.

Well weíll take those out now. And we can see really quite acceptable chin contour here and Mrs. Brooks if you could turn just a little bit to one side and uh okay.

Weíll get your chin up here a little bit again we need a background that isÖ But at any rate she was very prominent here where the tumor expanded her jaw and sheís back now to fairly normal proportion. Now weíll come back again. Straight ahead. Well for six weeks post-operatively Mrs. Brooks is doing extremely well. The initial healing is satisfactory.

Recalling the importance of close monitoring of these patients over long periods of time, however, because of the great tendency for this type of lesion to persist and to recur. Weíll want to keep close track of her and we will see her at monthly intervals probably offer at least the first year and then over a period of perhaps five years extend that to intervals of two and three month follow-up check-ups for clinical and radiographic surveillance. Thank you again Mrs. Brooks for coming in to see us. This is a follow-up visit for Mrs.

Brooks at three months after her surgery for the resection of her anterior mandible for the recurrent ameloblastoma. And we can see that her profile is certainly normal. She has reasonably good chin support. And as far as facial balance and configuration is concerned there is no evidence of the resection of the tumor. From the front we would see that she also has a reasonable proportion to her face and as we look into the mouth and put these retractors in position.

Now we will see with these retractors in position that the molar teeth, the only teeth that she has left in the mandible, are in occlusion, they are undisturbed. We have previously seen the split that was used to support the thinned out mandible where only the lingual plate was left. If she moves her chin down a little bit, and opens, if you could open Annie, and then moves her tongue back a little, you can see the configuration of what is residual ridge. There is only the lingual plate there and the vestibule is absent to the left of the midline where the soft tissue deficit was greatest and where the adhesion is attached at a higher level.

We have hopes that her mouth will be able to be restored so that some function can be regained. Now if you close your jaws again Annie. And then open again and close again. There is no functional deficit to the remaining mandible and the jaw is solid and her sensation in the areas of the metal nerve has not yet returned.

This is still a numb area, is it not, Annie? Is there any change at all here? Do you get any tingling yet or not? Mrs. Brooks: Sometimes. Dr. Hayward: Once in a while.

Well we think that at this stage in the game Mrs. Brooks is doing well and we hope that we can proceed with the prosthetic reconstruction for the missing teeth and alveolar bone. You have been listening to a presentation from the University of Michigan's School of Dentistry which is dedicated to supporting open learning and open educational resources. This recording is licensed under the creative comments. It may be reused and redistributed for nonprofit use. Please attribute materials to the University of Michigan's School of Dentistry and redistribute under this same license.

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