|Year : 2011 | Volume
| Issue : 6 | Page : 74-78
Ameloblastoma in children: Should we be radical?
S Sharma1, D Goyal1, A Ray2, N Gupta3
1 Department of Oral Surgery, Rajasthan Dental College and Hospital, Jaipur, Rajasthan, India
2 Department of Oral Surgery, Guru Nanak Dev Dental College, Shodpur, Kolkata, India
3 Department of Prosthodonics, Govt. Dental College and Hospital, Jaipur, Rajasthan, India
|Date of Web Publication||12-Dec-2011|
Department of Oral Surgery, B-57, Yash Path, Tilak Nagar, Jaipur - 302 004, Rajasthan
Source of Support: None, Conflict of Interest: None
| Abstract|| |
Ameloblastoma is the most common aggressive benign odontogenic tumor of the jaws. The tumor is often asymptomatic, presenting as a slowly enlarging facial swelling. The physical presence of the tumor may cause symptoms such as pain, ulceration, loosening of teeth, or malocclusion. Ameloblastoma is a locally destructive tumor with a propensity for recurrence if not entirely excised. It is seen in all age groups, but the lesion is most commonly diagnosed in the third and fourth decades. The tumor is considered a rarity in the young age group. The treatment of ameloblastoma is still controversial and presents some special problems in children like the growth of the jaw, the different incidence, behavior and prognosis of the tumor in children, which make the surgical considerations different from adults. Some reports have encouraged conservative treatment for ameloblastoma in children.
Keywords: Ameloblastoma, marsupialization, unicystic
|How to cite this article:|
Sharma S, Goyal D, Ray A, Gupta N. Ameloblastoma in children: Should we be radical?. J Indian Soc Pedod Prev Dent 2011;29, Suppl S1:74-8
|How to cite this URL:|
Sharma S, Goyal D, Ray A, Gupta N. Ameloblastoma in children: Should we be radical?. J Indian Soc Pedod Prev Dent [serial online] 2011 [cited 2020 Jan 21];29, Suppl S1:74-8. Available from: http://www.jisppd.com/text.asp?2011/29/6/74/90748
| Introduction|| |
According to the WHO 1992 definition, ameloblastoma is a benign but locally invasive polymorphic neoplasm consisting of proliferating odontogenic epithelium, which usually has a follicular or plexiform pattern, lying in a fibrous stroma.
Unicystic ameloblastoma, a variant of ameloblastoma first described by Robinson and Martinez , in 1977, refers to those cystic lesions that show clinical and radiologic characteristics of an odontogenic cyst but in histologic examination show a typical ameloblastomatous epithelium lining part of the cyst cavity, with or without luminal and/or mural tumor proliferation. They purported the unicystic variant as a less aggressive variant of ameloblastoma and suggested simple enucleation as the treatment.
The WHO histological typing of odontogenic tumors classifies ameloblastomas as intraosseous central and extraosseous peripheral types.  Within the central type, the unicystic variant is recognized as a clinically, radiologically, and pathologically distinct entity with prognostic significance that warrants alternative management to the classical central type. The intraosseous ameloblastoma of the jaws occurs most often in the fourth and fifth decades of life.  Its occurrence in children and adolescents younger than 18 years is uncommon, seen only in 14.6% of 206 cases of ameloblastomas.  Regez and Sciubba reported that ameloblastoma accounts for 11% of all odontogenic tumors in the jaw. 
The unicystic ameloblastoma is considered a variant of the solid or multicystic ameloblastoma, accounting for 6-15% of all intraosseous ameloblastomas.  This lesion occurs in a younger age group, with slightly more than 50% of cases occurring in patients in the second decade of life.  In more than 90% of the cases, the unicystic ameloblastoma is located in the mandible, with 77% located in the molar ramus region. 
The clinicopathologic features are benign with a slow-growing pattern, but locally invasive. The clinical behavior may be regarded as lying somewhere between benign and malignant, and the high recurrence rate is a problem for clinicians. , If the factors associated with recurrence are established and prediction of a recurrence is possible, this will be very important in reducing the recurrence rate and in the decision-making process of the appropriate treatment.
The literature indicates that the cystic variant is biologically less aggressive and has a better response to enucleation than the solid ameloblastoma.  Plexiform unicystic ameloblastoma does not exhibit the histological criteria for ameloblastoma given by Vickers and Gorlin. 
| Case Report|| |
An 11-year-old girl presented with hard swelling in the right side of the lower jaw since 1 year [Figure 1]. She gave a history of extraction of 47 done 1 month back. Clinical examination revealed a bony hard swelling arising from the lower jaw, with intraoral examination showing a large, hard, nontender mass on the right side of the mandible, which was covered by red, intact, and immobile mucosa [Figure 2]. On palpation, the swelling was bony hard. No lymphadenopathy or fistulae were present. Medical history was unremarkable.
On examination, no other abnormalities were found. She was taking no medication and had no history of known drug allergy. Her physical examination revealed no abnormality other than those related to the chief complaint.
Radiography revealed a large unilocular radiolucency extending from right mandibular first molar till sigmoid notch involving entire ramus and coronoid process [Figure 3]. The condylar stump was spared. A provisional diagnosis of odontogenic tumor was made and incisional biopsy was performed which confirmed plexiform unicystic ameloblastoma group I according to the classification given by Ackerman [Figure 4].  Marsupialization was performed with extraction of 46 [Figure 5]. Impacted third molar was not removed considering the thin rim of bone present at inferior border of mandible [Figure 6]. A whitehead varnish dressing was given and secured with sutures [Figure 7]. The dressing was changed frequently, first after the 3 rd day and later once in a week [Figure 8].
|Figure 4: Histopathology showing group 1 unicystic plexiform ameloblastoma|
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Panoramic radiograph was taken 3 months after the operation. There was significant change in the position of third molar tooth bud with deposition of bone at inferior border and posterior border of ramus of mandible. Second stage surgery was performed to remove the remaining lining of ameloblastoma with third molar tooth bud. Another panoramic radiograph was taken at 6 months which showed complete filling of cavity with bone [Figure 9]. There was still slight asymmetry present on the affected side at follow-up of 1 year [Figure 10].
| Discussion|| |
Unilocular ameloblastoma (UA) is a rare type of ameloblastoma, accounting for about 6% of ameloblastomas. It usually occurs in a younger age group, with about 50% of the cases occurring in the second decade of life. More than 90% lesions are located in the mandible. ,, Between 50 and 80% of the cases are associated with tooth impaction, the mandibular third molar being most often involved. Patients most commonly present with swelling and facial asymmetry, pain being an occasional presenting symptom. Mucosal ulceration is rare, but may be caused by continued growth of the tumor. Small lesions are sometimes discovered more on routine radiographic screening examinations or as a result of local effects (like tooth mobility, occlusal alterations and failure of eruption of teeth) produced by the tumor.  Histologically, the minimum criterion for diagnosing a lesion as UA is the demonstration of a single cystic sac lined by odontogenic (ameloblastomatous) epithelium often seen only in focal areas.
In a clinicopathologic study of 57 cases of unicystic ameloblastoma, Ackermann  classified this entity into the following three histologic groups:
Group I: Luminal UA (tumor confined to the luminal surface of the cyst)
Group II: Intraluminal/plexiform UA (nodular proliferation into the lumen without infiltration of tumor cells into the connective tissue wall)
Group III: Mural UA (invasive islands of ameloblastomatous epithelium in the connective tissue wall not involving the entire epithelium)
Another histologic subgrouping by Philipsen and Reichart  has also been described:
Subgroup 1: Luminal UA
Subgroup 1.2: Luminal and intraluminal
Subgroup 1.2.3: Luminal, intraluminal and intramural
Subgroup 1.3: Luminal and intramural
The UAs diagnosed as subgroups 1 and 1.2 can be treated conservatively (careful enucleation), whereas subgroups 1.2.3 and 1.3 showing intramural growths require treatment with radical resection, as for a solid or multicystic ameloblastoma.  Following enucleation, vigorous curettage of the bone should be avoided as it may implant foci of ameloblastoma more deeply into bone. Chemical cauterization with Carnoy's solution is also advocated for subgroups 1 and 1.2. Subgroups 1.2.3 and 1.3 have a high risk for recurrence, requiring more aggressive surgical procedures. This is because the cystic wall in these cases has islands of ameloblastoma tumor cells and there may be penetration into the surrounding cancellous bone. ,, Late recurrence following treatment is commonly seen, with the average interval for recurrence being 7 years. Recurrence is also related to histologic subtypes of UA, with those invading the fibrous wall having a rate of 35.7%, but others showing only 6.7% recurrence.  Recurrence rates are also related to the type of initial treatment. Lau et al. reported recurrence rates of 3.6% for resection, 30.5% for enucleation alone, 16% for enucleation followed by Carnoy's solution application, and 18% by marsupialization followed by enucleation (where the lesion reduced in size).
Recurrence of an ameloblastoma in large part reflects the inadequacy or failure of the primary surgical procedure.  The treatment is an important prognostic factor, as suggested in several studies. ,, Various treatment methods for the lesion in relation to many factors, such as the tumor size and location, have been suggested. These include enucleation, marginal resection and aggressive resection. In our case, histopathologic diagnosis was confirmed as plexiform unicystic ameloblastoma group I, so the treatment plan was decided as marsupialization followed by enucleation. Since the younger children have good capacity to regenerate the bone, marsupialization can allow bone formation at a better rate. In our opinion, it is better to deal with such unicystic ameloblastoma as dentigerous cyst rather than doing aggressive resection at an early age.
| Conclusion|| |
Unicystic ameloblastoma is a tumor with a strong propensity for recurrence, especially when the ameloblastic focus penetrates the adjacent tissue from the wall of the cyst. On the contrary, if the tumor is confined to the luminal surface of the cyst, then it can be safely enucleated. The ability to predict this potential occurrence prior to surgery would greatly enhance therapeutic strategies in the management of such cases.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6], [Figure 7], [Figure 8], [Figure 9], [Figure 10]
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