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Keratoameloblastoma of the mandible
G Model
ARTICLE IN PRESS
ANORL-630; No. of Pages 2
European Annals of Otorhinolaryngology, Head and Neck diseases xxx (2016) xxx–xxx
Available online at
ScienceDirect www.sciencedirect.com
Case report
Keratoameloblastoma of the mandible S. Anajar ∗ , A. Lakhbal , R. Abada , M. Mahtar ENT Department, Face and Neck Surgery, Hospital August, 20’1953, University Hospital Centre IBN ROCHD, street ait baha, boulevard Bordeaux No. 5, Casablanca, Morocco
a r t i c l e
i n f o
Keywords: Ameloblastoma Odontogenic tumor Mandible Keratin
a b s t r a c t Introduction: Keratoameloblastoma is an extremely rare odontogenic tumor, as only 18 cases have been reported in the literature. Case report: The authors report a case of keratoameloblastoma in a 32-year-old woman and review the literature concerning the clinical features, radiological appearance, histopathological findings and treatment options. Discussion: Keratoameloblastoma is a rare tumor observed more frequently in males (sex ratio: 3:1) characterized by extensive keratin production in odontogenic islets and fibrous stroma. © 2016 Published by Elsevier Masson SAS.
1. Introduction Ameloblastomas are benign, locally aggressive odontogenic tumors that represent about 1% of all odontogenic tumors. Ameloblastomas involve the mandible in 80% of cases and the maxilla in 20% of cases [1]. Keratoameloblastoma is considered to be a rare variant of ameloblastoma associated with more intense keratinization. The diagnostic and therapeutic difficulties raised by this tumor are discussed in the light of a case report.
Treatment consisted of wide resection of the tumor comprising the right mandible via a neck incision without primary reconstruction followed by maxillomandibular fixation (Fig. 3). Histopathological examination of the tumor concluded on a diagnosis of keratoameloblastoma based on the predominant epidermal component and the rim of columnar epithelium. The postoperative course was uneventful with a favorable clinical and radiological outcome 6 months after the operation. Secondary mandibular reconstruction with iliac crest bone graft was performed.
2. Case report 3. Discussion A 32-year-old woman was referred to our department by her general practitioner for painless right mandibular swelling, gradually evolving over a period of 4 years (Fig. 1). Clinical examination revealed a hard mass arising from the right mandible. Endobuccal examination revealed the absence of teeth 34 to 38. No mucocutaneous sensory disorders in the territory of the inferior alveolar nerve were detected and the rest of the physical examination was normal. Panoramic radiography demonstrated a multilocular osteolytic image of the right mandible (Fig. 2). Computed tomography revealed the presence of a multilocular osteolytic tumor expanding the cortex with zones of cortical destruction. A diagnosis of ameloblastoma was proposed at this stage. Biopsy of the gingival swelling was performed, suggesting a diagnosis of odontogenic myxoma.
∗ Corresponding author. E-mail address: [email protected] (S. Anajar).
Keratoameloblastoma was first described by Pindborg in 1970 [2]. The term “keratoameloblastoma” has been used to describe a histologically heterogeneous group of variants of ameloblastoma, sharing the common feature of keratin formation. This tumor is more common in males (61%) than in females (39%), and presents as a multilocular, destructive, space-occupying mass, essentially involving the mandible (78%). Maxillary keratoameloblastoma appears to be exceptional, but has been described in an African American woman [3]. This case of maxillary keratoameloblastoma illustrated the problems of histopathological differential diagnosis: extensive cystic formation with keratocystic components, but with a pavement epithelium in which the basal cells occasionally presented nuclear polarisation, and, most importantly, were cuboidal rather than columnar. This appearance was therefore suggestive of the presence of ameloblastoma arising in a odontogenic keratocyst, although a keratoameloblastoma possessing both solid and cystic components could not be excluded [3].
http://dx.doi.org/10.1016/j.anorl.2016.12.002 1879-7296/© 2016 Published by Elsevier Masson SAS.
Please cite this article in press as: Anajar S, et al. Keratoameloblastoma of the mandible. European Annals of Otorhinolaryngology, Head and Neck diseases (2016), http://dx.doi.org/10.1016/j.anorl.2016.12.002
G Model ANORL-630; No. of Pages 2 2
ARTICLE IN PRESS S. Anajar et al. / European Annals of Otorhinolaryngology, Head and Neck diseases xxx (2016) xxx–xxx
Fig. 1. Clinical appearance.
follicles containing orthokeratin, parakeratin, desquamated epithelium associated with necrotic material and dystrophic calcifications described in the premolar mandibular region of a young woman. In this case, the presence of ameloblast-like cells confirmed the diagnosis of ameloblastoma. However, certain features resembled those of keratoameloblastoma. Note that the presence of intense keratinization as well as tumor characteristics suggest that this tumor may simply be a variant of acanthomatous ameloblastoma [6]. The cases reported in the literature as keratoameloblastoma include a broad spectrum composed of variable histopathological features, which would explain the very heterogeneous management of published cases, ranging from enucleation to hemimandibulectomy and partial maxillectomy. Although keratoameloblastoma is a combination of two benign but aggressive lesions and is not encapsulated, wide excision combined with close clinical follow-up appears to be appropriate treatment [7,8]. The proposed types of reconstruction are the same as for mandibular ameloblastoma [10]. The outcome of patients after treatment is poorly defined. Two of the 18 cases reported in the literature developed recurrence, but the small number of published cases does not allow reliable estimation of the keratoameloblastoma recurrence rate [9,10]. Due to the small number of published cases and the insufficient posttreatment follow-up, a possible difference in the prognosis of keratoameloblastoma compared to other histopathological types of ameloblastoma cannot be evaluated. No cases of local or distant metastases or death due to keratoameloblastoma have been reported [8]. 4. Conclusion
Fig. 2. Dental panoramic radiography.
Keratoameloblastoma is a very rare tumor that shares common clinical features with all odontogenic tumors and requires the same type of treatment. It differs from other odontogenic tumors by its specific histopathological features, but whether it constitutes a distinct entity remains a subject of controversy. More cases need to be reported in order to precisely assess the prognosis of this tumor. Disclosure of interest The authors declare that they have no competing interest. References
Fig. 3. Appearance of the operative specimen.
These characteristics can be summarized as follows: islets of epithelial tumor cells with a papilliferous appearance, keratinizing cysts and multiple keratin pearls. Four other cases of ameloblastoma with odontogenic keratocyst, or a rare variant of keratinized ameloblastoma have subsequently been reported [4]. In 1991, Altini et al. suggested that these two variants do not constitute distinct entities, but correspond to two variants of ameloblastoma. They considered these tumors to be epithelial odontogenic tumors, but the classification of these tumors has not yet been defined [5]. A similar case was reported by Norval et al. [6] in 1994, corresponding to an unusual case of ameloblastoma composed of cystic
[1] Sisto JM, Olsen GG. Keratoameloblastoma: complex histologic variant of ameloblastoma. J Oral Maxillofac Surg 2012:70860–4. [2] Pindborg JJ. Pathology of the dental hard tissues. Philadelphia (PA): W.B. Saunders; 1970. p. 371–6. [3] Said-al-Naief NA, Lumerman H, Ramer M, et al. Keratoameloblastoma of the maxilla. A case report and review of the literature. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 1997:84535–9. [4] Siar CH, Ng KH. Combined ameloblastoma and odontogenic keratocyst or keratinising ameloblastoma. Br J Oral Maxillofac Surg 1993;31:183–6. [5] Altini M, Slabbert HD, Johnston T. Papilliferous keratoameloblastoma. J Oral Pathol Med 1991;20:46–8. [6] Norval EJ, Thompson IO, van Wyk CW. An unusual variant of keratoameloblastoma. J Oral Pathol Med 1994;23:465–7. [7] Lee C, Park BJ, Yi WJ, et al. Keratoameloblastoma: a case report and a review of the literature on its radiologic features. Oral Surg Oral Med Oral Pathol Oral Radiol 2015;120:219–25. [8] Whitt JC, Dunlap CL, Sheets JL, et al. Keratoameloblastoma: a tumor sui generis or a chimera? Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2007;104:368–76. [9] Bedi RS, Sah K, Singh A, Chandra S, Raj V. Keratoameloblastoma or keratoodontoameloblastoma: report of its soft tissue recurrence with literature review. Quant Imaging Med Surg 2015;5:898–908. [10] Netto R, Cortezzi W, Merly F, et al. Keratoameloblastoma: a rare case of recidivation of a rare lesion. Int J Oral Maxillofac Surg 2013;42:1174.
Please cite this article in press as: Anajar S, et al. Keratoameloblastoma of the mandible. European Annals of Otorhinolaryngology, Head and Neck diseases (2016), http://dx.doi.org/10.1016/j.anorl.2016.12.002
ARTICLE IN PRESS
ANORL-630; No. of Pages 2
European Annals of Otorhinolaryngology, Head and Neck diseases xxx (2016) xxx–xxx
Available online at
ScienceDirect www.sciencedirect.com
Case report
Keratoameloblastoma of the mandible S. Anajar ∗ , A. Lakhbal , R. Abada , M. Mahtar ENT Department, Face and Neck Surgery, Hospital August, 20’1953, University Hospital Centre IBN ROCHD, street ait baha, boulevard Bordeaux No. 5, Casablanca, Morocco
a r t i c l e
i n f o
Keywords: Ameloblastoma Odontogenic tumor Mandible Keratin
a b s t r a c t Introduction: Keratoameloblastoma is an extremely rare odontogenic tumor, as only 18 cases have been reported in the literature. Case report: The authors report a case of keratoameloblastoma in a 32-year-old woman and review the literature concerning the clinical features, radiological appearance, histopathological findings and treatment options. Discussion: Keratoameloblastoma is a rare tumor observed more frequently in males (sex ratio: 3:1) characterized by extensive keratin production in odontogenic islets and fibrous stroma. © 2016 Published by Elsevier Masson SAS.
1. Introduction Ameloblastomas are benign, locally aggressive odontogenic tumors that represent about 1% of all odontogenic tumors. Ameloblastomas involve the mandible in 80% of cases and the maxilla in 20% of cases [1]. Keratoameloblastoma is considered to be a rare variant of ameloblastoma associated with more intense keratinization. The diagnostic and therapeutic difficulties raised by this tumor are discussed in the light of a case report.
Treatment consisted of wide resection of the tumor comprising the right mandible via a neck incision without primary reconstruction followed by maxillomandibular fixation (Fig. 3). Histopathological examination of the tumor concluded on a diagnosis of keratoameloblastoma based on the predominant epidermal component and the rim of columnar epithelium. The postoperative course was uneventful with a favorable clinical and radiological outcome 6 months after the operation. Secondary mandibular reconstruction with iliac crest bone graft was performed.
2. Case report 3. Discussion A 32-year-old woman was referred to our department by her general practitioner for painless right mandibular swelling, gradually evolving over a period of 4 years (Fig. 1). Clinical examination revealed a hard mass arising from the right mandible. Endobuccal examination revealed the absence of teeth 34 to 38. No mucocutaneous sensory disorders in the territory of the inferior alveolar nerve were detected and the rest of the physical examination was normal. Panoramic radiography demonstrated a multilocular osteolytic image of the right mandible (Fig. 2). Computed tomography revealed the presence of a multilocular osteolytic tumor expanding the cortex with zones of cortical destruction. A diagnosis of ameloblastoma was proposed at this stage. Biopsy of the gingival swelling was performed, suggesting a diagnosis of odontogenic myxoma.
∗ Corresponding author. E-mail address: [email protected] (S. Anajar).
Keratoameloblastoma was first described by Pindborg in 1970 [2]. The term “keratoameloblastoma” has been used to describe a histologically heterogeneous group of variants of ameloblastoma, sharing the common feature of keratin formation. This tumor is more common in males (61%) than in females (39%), and presents as a multilocular, destructive, space-occupying mass, essentially involving the mandible (78%). Maxillary keratoameloblastoma appears to be exceptional, but has been described in an African American woman [3]. This case of maxillary keratoameloblastoma illustrated the problems of histopathological differential diagnosis: extensive cystic formation with keratocystic components, but with a pavement epithelium in which the basal cells occasionally presented nuclear polarisation, and, most importantly, were cuboidal rather than columnar. This appearance was therefore suggestive of the presence of ameloblastoma arising in a odontogenic keratocyst, although a keratoameloblastoma possessing both solid and cystic components could not be excluded [3].
http://dx.doi.org/10.1016/j.anorl.2016.12.002 1879-7296/© 2016 Published by Elsevier Masson SAS.
Please cite this article in press as: Anajar S, et al. Keratoameloblastoma of the mandible. European Annals of Otorhinolaryngology, Head and Neck diseases (2016), http://dx.doi.org/10.1016/j.anorl.2016.12.002
G Model ANORL-630; No. of Pages 2 2
ARTICLE IN PRESS S. Anajar et al. / European Annals of Otorhinolaryngology, Head and Neck diseases xxx (2016) xxx–xxx
Fig. 1. Clinical appearance.
follicles containing orthokeratin, parakeratin, desquamated epithelium associated with necrotic material and dystrophic calcifications described in the premolar mandibular region of a young woman. In this case, the presence of ameloblast-like cells confirmed the diagnosis of ameloblastoma. However, certain features resembled those of keratoameloblastoma. Note that the presence of intense keratinization as well as tumor characteristics suggest that this tumor may simply be a variant of acanthomatous ameloblastoma [6]. The cases reported in the literature as keratoameloblastoma include a broad spectrum composed of variable histopathological features, which would explain the very heterogeneous management of published cases, ranging from enucleation to hemimandibulectomy and partial maxillectomy. Although keratoameloblastoma is a combination of two benign but aggressive lesions and is not encapsulated, wide excision combined with close clinical follow-up appears to be appropriate treatment [7,8]. The proposed types of reconstruction are the same as for mandibular ameloblastoma [10]. The outcome of patients after treatment is poorly defined. Two of the 18 cases reported in the literature developed recurrence, but the small number of published cases does not allow reliable estimation of the keratoameloblastoma recurrence rate [9,10]. Due to the small number of published cases and the insufficient posttreatment follow-up, a possible difference in the prognosis of keratoameloblastoma compared to other histopathological types of ameloblastoma cannot be evaluated. No cases of local or distant metastases or death due to keratoameloblastoma have been reported [8]. 4. Conclusion
Fig. 2. Dental panoramic radiography.
Keratoameloblastoma is a very rare tumor that shares common clinical features with all odontogenic tumors and requires the same type of treatment. It differs from other odontogenic tumors by its specific histopathological features, but whether it constitutes a distinct entity remains a subject of controversy. More cases need to be reported in order to precisely assess the prognosis of this tumor. Disclosure of interest The authors declare that they have no competing interest. References
Fig. 3. Appearance of the operative specimen.
These characteristics can be summarized as follows: islets of epithelial tumor cells with a papilliferous appearance, keratinizing cysts and multiple keratin pearls. Four other cases of ameloblastoma with odontogenic keratocyst, or a rare variant of keratinized ameloblastoma have subsequently been reported [4]. In 1991, Altini et al. suggested that these two variants do not constitute distinct entities, but correspond to two variants of ameloblastoma. They considered these tumors to be epithelial odontogenic tumors, but the classification of these tumors has not yet been defined [5]. A similar case was reported by Norval et al. [6] in 1994, corresponding to an unusual case of ameloblastoma composed of cystic
[1] Sisto JM, Olsen GG. Keratoameloblastoma: complex histologic variant of ameloblastoma. J Oral Maxillofac Surg 2012:70860–4. [2] Pindborg JJ. Pathology of the dental hard tissues. Philadelphia (PA): W.B. Saunders; 1970. p. 371–6. [3] Said-al-Naief NA, Lumerman H, Ramer M, et al. Keratoameloblastoma of the maxilla. A case report and review of the literature. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 1997:84535–9. [4] Siar CH, Ng KH. Combined ameloblastoma and odontogenic keratocyst or keratinising ameloblastoma. Br J Oral Maxillofac Surg 1993;31:183–6. [5] Altini M, Slabbert HD, Johnston T. Papilliferous keratoameloblastoma. J Oral Pathol Med 1991;20:46–8. [6] Norval EJ, Thompson IO, van Wyk CW. An unusual variant of keratoameloblastoma. J Oral Pathol Med 1994;23:465–7. [7] Lee C, Park BJ, Yi WJ, et al. Keratoameloblastoma: a case report and a review of the literature on its radiologic features. Oral Surg Oral Med Oral Pathol Oral Radiol 2015;120:219–25. [8] Whitt JC, Dunlap CL, Sheets JL, et al. Keratoameloblastoma: a tumor sui generis or a chimera? Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2007;104:368–76. [9] Bedi RS, Sah K, Singh A, Chandra S, Raj V. Keratoameloblastoma or keratoodontoameloblastoma: report of its soft tissue recurrence with literature review. Quant Imaging Med Surg 2015;5:898–908. [10] Netto R, Cortezzi W, Merly F, et al. Keratoameloblastoma: a rare case of recidivation of a rare lesion. Int J Oral Maxillofac Surg 2013;42:1174.
Please cite this article in press as: Anajar S, et al. Keratoameloblastoma of the mandible. European Annals of Otorhinolaryngology, Head and Neck diseases (2016), http://dx.doi.org/10.1016/j.anorl.2016.12.002