|Year : 2015 | Volume
| Issue : 2 | Page : 302-306
Ameloblastic carcinoma: A case series
Appaji Athota1, Leela Vasundhar Paladugu2, Usha Konidala3, Gokkul krishnan4
1 Department of Oral Medicine and Radiology, DJ College of Dental Sciences, Modinagar, Uttar Pradesh, India
2 Department of Oral and Maxillofacial Surgery, Dr Sudha and Nageshwarao Siddhartha Institute Dental Sciences, Allapuram, Tamil Nadu, India
3 Department of Pedodontics, Dr Sudha and Nageshwarao Siddhartha Institute Dental Sciences, Allapuram, Tamil Nadu, India
4 Department of Oral and Maxillofacial Surgery, GITAM Dental College and Hospital, Visakhapatnam, Andhra Pradesh, India
|Date of Submission||31-Jan-2015|
|Date of Acceptance||08-Oct-2015|
|Date of Web Publication||21-Nov-2015|
Department of Oral Medicine and Radiology, DJ College of Dental Sciences, Modinagar, Uttar Pradesh
Source of Support: None, Conflict of Interest: None
| Abstract|| |
Ameloblastic carcinoma is a rare odontogenic tumor exhibiting not only features of ameloblastoma but also features of carcinoma in either or both primary and metastatic lesions. Clinical features of this lesion are more aggressive and rapid than those of ameloblastoma. At times, it can metastasize to the lung or regional lymph nodes. Histologically, there is a picture of both ameloblastoma and carcinoma. Treatment is aggressive and has to be designed for each individual patient. English literature is sparse for this condition, as fewer cases have been reported till date. We report a series of four cases with different treatment modalities.
Keywords: Ameloblastic carcinoma, odontogenic, tumor
|How to cite this article:|
Athota A, Paladugu LV, Konidala U, krishnan G. Ameloblastic carcinoma: A case series. J Indian Acad Oral Med Radiol 2015;27:302-6
|How to cite this URL:|
Athota A, Paladugu LV, Konidala U, krishnan G. Ameloblastic carcinoma: A case series. J Indian Acad Oral Med Radiol [serial online] 2015 [cited 2019 Sep 17];27:302-6. Available from: http://www.jiaomr.in/text.asp?2015/27/2/302/170166
| Introduction|| |
In 1952, Robinson defined ameloblastoma as a tumor that is "unicentric, nonfunctional, intermittent in growth, anatomically benign, and clinically persistent."  It is a relatively common benign odontogenic tumor classified as tumor of odontogenic epithelium without odontogenic ectomesenchyme. Malignant ameloblastoma and ameloblastic carcinoma are two distinct variants of ameloblastoma. Ameloblastic carcinoma may be locally aggressive and may or may not undergo regional lymph node metastasis, whereas malignant ameloblastoma definitely shows metastasis.  Clinical features of both these lesions are aggressive as compared to conventional ameloblastoma. Histopathology plays a vital role in differentiating these three lesions. Choice of treatment also differs for all these three conditions. Regional lymph node dissection should be considered when required in cases of ameloblastic carcinoma, whereas it is mandatory for malignant ameloblastoma and not required for conventional ameloblastoma. Radiotherapy (RT) and chemotherapy seem to be of limited value. Close and long-term follow-up is required especially for aggressive lesions.
| Case Reports|| |
A 25-year-old female reported to our department with a chief complaint of pain and swelling in the lower left back teeth region since 6 months. History revealed that the patient was apparently asymptomatic 6 months back when she noticed pain and swelling in the mandibular left angle region. The swelling increased in size gradually and was associated with pus discharge for 10 days. On examination, there was mild facial asymmetry with an extraoral swelling in the left mandibular angle region [Figure 1]a extending superoinferiorly from the ala-tragus line to the lower border of mandible and anteroposteriorly from the corner of the mouth to the postauricular region. The swelling was firm and tender on palpation. Intraorally, a firm swelling extending from the left mandibular molar area to retromolar pad was seen, with bicortical expansion [Figure 1]b]. Radiographic examination revealed a well-circumscribed, multilocular radiolucent lesion extending from 37 region up to the neck of mandible, which was confirmed with computed tomographic (CT) scan [Figure 1]c]. Aspiration was negative. Following incisional biopsy, histopathological examination revealed hyperchromatic ameloblast-like cells with pleomorphism and reverse polarity, which was suggestive of ameloblastic carcinoma. Under general anesthesia, through an extended submandibular incision, segmental resection of the mandible was done. The lesion was excised in toto and was sent for histopathological examination, which confirmed ameloblastic carcinoma with clear margins. Patient has been followed up till date (32 months) with no evidence of any metastasis or recurrence as seen in the postoperative radiograph [Figure 1]d.
|Figure 1: (a) Extraoral pre-operative view with swelling on the left side of the face. (b) Intraoral pre-operative view with bicortical expansion. (c) Pre-operative CT scan. (d) Post-operative radiograph|
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A 34-year-old male reported to our department with a chief complaint of numbness and swelling on the right side of face since 5 months. History revealed that the patient noticed swelling on the right side of face 5 months back, which increased in size rapidly and became associated with numbness in the past 1 month. On examination, there was facial asymmetry with an extraoral diffuse, firm, and non-tender swelling [Figure 2]a extending from the zygomatic process to the inferior border of mandible. Right submandibular lymph nodes (level II) were palpable and fixed. Intraorally, the swelling was diffuse with no surface ulcerations. Radiographic examination revealed a well-defined, unilocular radiolucency extending from 36 to 38 region [Figure 2]b. Aspiration was negative. Following incisional biopsy, histopathological examination revealed presence of hyperchromatic, ameloblast-like cells arranged in a typical sheet and cord pattern. Based on this, a final diagnosis of ameloblastic carcinoma was made. Under general anesthesia, right hemimandibulectomy was done excising the lesion in toto, followed by right supraomohyoid neck dissection clearing levels I, II, and III [Figure 2]c. Reconstruction was achieved with reconstruction plate [Figure 2]d]. Patient is being followed up till date (22 months) with no evidence of disease or metastasis.
|Figure 2: (a) Extraoral pre-operative view with marked swelling on the right side of the face. (b) Pre-operative orthopantomograph (OPG). (c) Intraoperative neck dissection. (d) Post-operative OPG|
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A 27-year-old female reported to us with a complaint of swelling, pain, and pus discharge in relation to the left posterior mandible. History revealed that 3 months earlier, the patient developed pain and swelling in the mandibular left angle region; the swelling increased in size gradually and became associated with pus discharge in the past 10 days. On examination, there was mild facial asymmetry with an extraoral firm and tender swelling in the left mandibular angle region, extending from the postauricular region to the corner of the mouth. Intraorally, a firm swelling extending from 34 to 38 region was present [Figure 3]a. Radiographic examination revealed a well-defined, radiolucent lesion extending from 33 region to ramus of the mandible [Figure 3]b]. Aspiration was negative. Following incisional biopsy, histopathological examination revealed parakeratinized stratified squamous epithelium and highly cellular connective tissue stroma with sheets and cords of cells appearing ameloblast like with reversal of polarity and hyperchromatism, which was suggestive of ameloblastic carcinoma. Under general anesthesia, segmental resection of the mandible was done. Reconstruction was achieved with a reconstruction plate [Figure 3]c]. The excised lesion [Figure 3]d was sent for histopathological examination, which confirmed ameloblastic carcinoma. Patient is being followed up till date (39 months) with no evidence of disease.
|Figure 3: (a) Intraoral pre-operative view with proliferative growth. c (b) Pre-operative OPG. (c) Intraoperative view with reconstruction plate in position. (d) Excised lesion|
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A 60-year-old male reported to our department with a chief complaint of swelling and ulceration in the lower right back teeth region since 2 months. History revealed that the patient was apparently all right 2 months back when he noticed pain in the mandibular right angle region for which his 48 was extracted by a local practitioner. Fifteen days after extraction, the patient noticed a growth in the same region which was associated with mild pain and ulceration. On examination, there was an ulceroproliferative growth in 48 region [Figure 4]a which was tender on palpation. Right single submandibular lymph node was palpable and was mobile and tender. Radiographic examination revealed an ill-defined, unilocular radiolucent lesion in the 48 region [Figure 4]b], extending from the distal aspect of 47 to the ramus region involving both the cortices. Aspiration was negative. Following incisional biopsy, histopathological examination revealed pleomorphic and hyperchromatic ameloblast-like cells with reversal of polarity, which was suggestive of ameloblastic carcinoma [Figure 4]c]. Hemimandibulectomy along with supraomohyoid neck dissection under general anesthesia was planned, but unfortunately the patient was not interested in treatment and was lost for follow-up.
|Figure 4: (a) Intraoral pre-operative view. (b) Pre-operative OPG. (c) Histopathological picture|
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| Discussion|| |
Ameloblastic carcinoma is a rare malignant lesion with characteristic histologic features and behavior that dictate a more aggressive surgical approach than other forms of ameloblastoma. However, reliable evidence of its biologic activity is currently unavailable due to the scarcity of well-documented cases. Only 37 cases have been reported in the English language literature from 1984 to 2007, which were mainly single cases.  In 1983, Shafer et al.  introduced the term ameloblastic carcinoma to describe ameloblastomas in which there had been histologic malignant transformation.
Ameloblastic carcinoma occurs in a wide range of age groups. According to Sciubba et al., the mean age is 30.5 years, male to female ratio is 1.5:1, and 80% of the tumors are located in the mandible,  more frequently in the posterior region than in the anterior region.  According to Okada et al.,  two-thirds of the affected females were in the age group of 20-40 years, which is similar to that in this report as four out of five patients reported here were in this age group, and in all cases, posterior mandible was involved. There is no apparent sex predilection. The most commonly involved area is the posterior portion of the mandible.  Involvement of the maxilla seems to be less frequent than that of the mandible. ,, Ameloblastic carcinoma has been reported to arise either de novo, ex odontogenic cyst, or ex ameloblastoma. 
The clinical course of ameloblastic carcinoma is typically aggressive, with extensive local destruction. Direct extension of the tumor, lymph node involvement, and metastasis to various sites (frequently the lung) have been reported. Clinical symptoms of ameloblastic carcinomas are more aggressive than those of conventional ameloblastomas, usually being associated with swelling, pain, rapid growth, trismus, dysphonia, expansion of the jaws, and, frequently, perforation of the cortex.  Radiographic appearance of ameloblastic carcinoma is consistent with that of ameloblastoma except for the occasional presence of some focal radiopacities, apparently reflecting dystrophic calcification. Corio et al. reported eight cases of ameloblastic carcinoma and stated that in most cases, radiographically, there was an ill-defined destructive radiolucency, with occasional radiopacities.  Histologically, ameloblastic carcinoma does not show uniform proliferation, and has pleomorphic and hyperchromatic cells arranged in the form of sheets and chords with reversed polarity.  Spindling of the cells is recognized in some solid proliferating areas.  Because the lesion is usually found unexpectedly after an incisional biopsy or removal of a cyst, a guide to differential diagnosis is not usually useful.
As far as treatment is concerned, wide local excision is the treatment of choice as most investigators have recommended, ,, and we had followed it in three of our cases. Some authors recommend en bloc resection with a margin of 2-3 mm.  Segmental resection with a good margin of 2-3 mm followed by reconstruction using titanium plates has also been advocated by certain authors.  For cases in which surgery is not possible and are non-conducive for surgery, chemotherapy and RT have been used, although it has been reported by Hall et al. in their study of 14 cases that RT alone without surgery has shown more propensity to recurrences.  Extensive lesions requiring mutilating surgeries may be treated with carbon ion therapy which can also be used in cases of relapse.  Regional lymph node dissection should be considered and performed selectively, as we had followed in one of our cases wherein the submandibular lymph node was fixed. The efficacy of adjuvant radiation or chemotherapy as a postsurgical treatment is not clear and seems to have a limited value. Based on the results of Gardner, RT can produce regression of an ameloblastoma, particularly the part which causes expansion of the jaw or has invaded the adjacent soft tissues, and it is an appropriate treatment only for unresectable tumors.  Data pertaining to chemotherapy are sparse and only anecdotal reports are available. Lanham described a case report of ameloblastoma metastasis to the lungs and nodes that was treated with doxorubicin, cisplatin, cyclophosphamide, dacarbazine, and 5-fluorouracil, but the tumor failed to respond. Grunwald et al. have reported excellent response to paclitaxel and carboplatin combination.  Neither chemotherapy nor RT has shown significant benefit, but they need to be considered in advanced cases and for metastatic lesions not amenable to surgical resection.  In a study by Yoon et al., distant metastasis occurred as early as 4 months and as late as 47 months after surgery.  Following radical surgical resection, close periodic reassessment of the patient is mandatory. In our case series, the least follow-up till date is 22 months and the maximum follow-up is 39 months, and all patients are still being followed without any signs of recurrence or metastasis.
| Conclusion|| |
It is reasonable to assume that this small series of cases illustrates the malignant variant in the spectrum of ameloblastomas and it is possible that ameloblastoma may show a wide variety of histologic and biologic behaviors ranging from being benign to frank malignancy. Cases of ameloblastoma should thus be studied carefully, correlating their histologic pattern with biologic behavior to detect subtle changes in histology that may predict aggressive behavior. Whenever a case is diagnosed as ameloblastic carcinoma, nodal metastasis should be assessed and evidence of distant metastasis should be evaluated before making a treatment plan. Treatment of ameloblastic carcinoma is controversial, but the recommended treatment is wide surgical resection. If evidence of nodal metastasis is present, then neck dissection should also be considered. Documented case reports with meaningful follow-up are rare. Meticulous follow-up is essential because recurrence and metastasis in the lung and regional lymph nodes have been reported. Role of RT is not very conclusive; however, presurgical radiation therapy has been suggested to decrease the tumor size, but chemotherapy is as yet unproven.
Declaration of Patient Consent
The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
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Conflicts of interest
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[Figure 1], [Figure 2], [Figure 3], [Figure 4]