Histopathology 2015, 66, 603–612.
Correspondence Primordial odontogenic tumour: is it truly novel? DOI: 10.1111/his.12595 © 2014 John Wiley & Sons Ltd
Sir: We would like to express our views regarding the recently published paper by Mosqueda-Taylor et al.1 on primordial odontogenic tumour (POT), which they considered to be a previously undescribed, benign ectomesenchymal neoplasm. We agree with the authors that all six of the lesions presented have many features of interest and importance with regard to classification and pathogenesis, and appear not to correspond to any of the accepted diagnostic categories. However, we question their claims of first description of this tumour type. Differences in nomenclature exist, and the previously published cases of ameloblastoma, ameloblastic fibroma, odontogenic fibroma and odontogenic myxoma are assumed to represent the same pathological process, nine of these accounts actually corresponding to previous descriptions of POT both clinically and pathologically.2–10 Although, at the time, none of these lesions were considered to be a distinct entity, odontogenic myxofibromas coated by a single layer of enamel epithelium have long been well known (References S1). Bernier,11 Tiecke12 and Gorlin,13 oral pathologists of great renown, illustrated a tumour compatible with POT in their seminal publications written approximately half a century ago. We understand that Mosqueda-Taylor et al.1 did not take into account the above reports because some of them were not indexed in PubMed, and their pathological repertoire did not include a superficial smattering of Japanese. Considering that six cases have been reported from Latin America1 and at least five from Japan,5,6,8–10 more examples of this type of tumour might be found in the local domestic scientific literature worldwide (References S1 and S2). Thus POT, previously unrecognized by Mosqueda-Taylor et al.1, may not be as rare as the authors suggest. At present, it is reasonable to consider that POT may arise during the course of embryonic, fetal or early postnatal development, not because of its marked structural resemblance to primitive dental tissues (papilla and follicle) but because of its usual association with anomalies of dental development, including
missing, malformed or unerupted teeth and its limited period of onset before adult life. It may well be that the surface enamel epithelium of POT often invaginates into the mesenchymal component in a manner and pattern reminiscent of normal odontogenesis, leading to its characteristic multilobulated configuration.1–8,10 Such a continuous double epithelial layer is occasionally expanded at the free end to form a microcystic space.1,2,5,7,8,10 Also of note is the presence of several fragments of fibrous tumour lacking a surface epithelial lining.4,6,8 Other examples of this histogenetic interest are dentigerous ameloblastic fibroma and odontogenic fibroma with sparse epithelial strands along the periphery of the tumour (References S3). In summary, there are two tumour mesenchymal patterns of POT, cell-rich (ameloblastic fibromalike)1–3,5,7,8,10 and cell-poor (odontogenic fibromyxoma-like) types.1,4,6,9 Accordingly, some doubt exists as to the exact nature of POT and whether it is truly a newly recognized embryonal tumour of immature dental tissues exhibiting the neoplastic characteristic of progressive growth, or whether it is merely a particular subset (architectural morphological variant) of ameloblastic fibroma or odontogenic fibroma/myxoma of dentigerous type arising during active dental development. Moreover, consideration should be given to the possibility that the cell-rich type may represent the primitive stage of a developing ameloblastic fibroma. The unique combination of proliferating fibrous and covering epithelial elements, a key diagnostic feature,1 accounts for the biphasic growth pattern of POT, thus leaving its ectomesenchymal or mixed epithelial– ectomesenchymal origin an open question.
Conflicts of interest No authors have any relevant financial disclosures or conflict of interest. Fumio Ide Kentaro Kikuchi Kaoru Kusama Takashi Muramatsu1 Division of Oral Pathology, Department of Diagnostic and Therapeutic Sciences, Meikai University School of Dentistry, Saitama, Japan, and 1Department of Endodontics and Clinical Cariology, Tokyo Dental College, Tokyo, Japan
604
Correspondence
1. Mosqueda-Taylor A, Pires FR, Aguirre-Urizar JM et al. Primordial odontogenic tumour: clinico-pathologic analysis of six cases of a previously undescribed entity. Histopathology 2014; 65; 606–612. 2. Hunter HA, Nikiforuk G. Ameloblastoma in a 3-year-old boy. Oral Surg. Oral Med. Oral Pathol. 1954; 7; 906–909. 3. MacLennan WD, McKendrick AJW. Unusual odontogenic tumor: report of case. J. Oral Surg. Anesth. Hosp. Dent. Serv. 1963; 21; 429–431. 4. Main DMG. Fibroma of the mandible. Br. J. Oral Surg. 1965; 3; 172–176. 5. Tomita K, Kawamura M, Fujimori T et al. A case of ameloblastic fibroma arising in the maxilla [Japanese abstract]. Jpn J. Oral Surg. 1972; 18; 653. 6. Inoue Y, Ishikawa K, Jinno T et al. A case of odontogenic myxofibroma [Japanese with English abstract]. Aichi-Gakuin J. Dent. Sci. 1979; 17; 87–93. 7. Meyers AD, Poulson T, Pettigrew J, Clark M. Cystic ameloblastic fibroma. Ear Nose Throat J. 1991; 70; 729–732. 8. Sakaki T, Kaji R, Wato M, Miyagawa T, Otake S, Mushimoto K. A segmental ameloblastic fibroma in the maxilla [Japanese with English abstract]. Jpn J. Oral Maxillofac. Surg. 1993; 39; 481–483. 9. Morita S, Jogetsu K, Nosaka Y, Tsunokuma M, Akane M, Okano H. A case of odontogenic fibroma in the mandible of a three-year-old boy [Japanese with English abstract]. Jpn J. Oral Maxillofac. Surg. 1994; 40; 935–937. 10. Semba I. Histological classification of odontogenic tumors and cysts [Japanese with English abstract]. Dent. Radiol. 1996; 36; 137–152. 11. Bernier JL. Odontogenic tumors. NY State. Dent. J. 1947; 13; 560–567. 12. Tiecke RW, Stuteville OH, Calandra JC eds. Pathologic physiology of oral disease. St Louis: CV Mosby, 1959; 312–313. 13. Gorlin RJ, Chaudhry AP, Pindborg JJ. Odontogenic tumors. Classification, histopathology, and clinical behavior in man and domesticated animals. Cancer 1961; 14; 73–101.
Supporting Information Additional Supporting Information may be found in the online version of this article: References S1. Odontogenic fibroma with a superficial covering of enamel epithelium. References S2. Odontogenic myxoma surfaced by other types of epithelium. References S3. Dentigerous ameloblastic fibroma or odontogenic fibroma with large areas devoid of epithelium.
Reply: Primordial odontogenic tumour: it is truly novel DOI: 10.1111/his.12605 © 2014 John Wiley & Sons Ltd
Sir: We would like to thank Ide et al.1 for their comments, interest and collaboration to obtain a better
understanding of the recently reported primordial odontogenic tumour (POT). We apologize for not reading Japanese but, as English is the main scientific international language, PubMed/MEDLINE represents the world reference for searching peer-reviewed scientific literature in medicine. In our article,2 we presented a series of six tumours sharing clinical, radiographic and microscopic findings that allowed us to consider them to be a specific entity that had not been previously described. The cases were collected from diverse geographical areas according to the origin of the authors, including Latin America and Europe (Spain). As Ide et al.1 pointed out, there may be, as may have occurred with several other entities when first reported, the possibility of some isolated cases of odontogenic tumours with findings similar to POT reported in old literature and/or in languages different to English, but, unfortunately, such cases were not highlighted and recognized as a distinct or specific entity. On the contrary, the cases that they claim as possible POT were considered to be examples of well-recognized odontogenic tumours such as ameloblastoma, myxofibroma, ameloblastic fibroma, or odontogenic fibroma. Assuming that some of these cases could be classified (after our definition of POT) as examples of this novel entity, which is very difficult to confirm by just reading the publications in which references are made to the existence of odontogenic fibroma, ameloblastic fibroma, or a myxofibroma partly coated by a single layer of odontogenic epithelium (which may occur when these lesions are fused to a dental follicle or by tangenctial sectioning), or when an ameloblastic fibroma is located in a dentigerous relationship, it would be interesting to consider them as an important part of the history of this entity, supporting the acceptance of this lesion as a new odontogenic tumour. The citations in which Ide et al.1 claim to find cases of POT refer mainly to Japanese reports and old articles and textbooks, which used terms such as ‘ameloblastoma’, ‘ameloblastic fibroma’, ‘odontogenic myxofibroma’, ‘cystic ameloblastic fibroma’, and ‘odontogenic fibroma’, which are entities that have been properly discussed as differential diagnoses of POT in our article,2 in which we emphasize those aspects that allow their differentiation from this tumour. In our study, special care was taken to discard ameloblastic fibroma, odontogenic fibroma and myxoma, based on findings previously described by other authors3 and studied and published by our own group.4,5 Histopathology, 66, 603–612.
Copyright of Histopathology is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use.
Correspondence Primordial odontogenic tumour: is it truly novel? DOI: 10.1111/his.12595 © 2014 John Wiley & Sons Ltd
Sir: We would like to express our views regarding the recently published paper by Mosqueda-Taylor et al.1 on primordial odontogenic tumour (POT), which they considered to be a previously undescribed, benign ectomesenchymal neoplasm. We agree with the authors that all six of the lesions presented have many features of interest and importance with regard to classification and pathogenesis, and appear not to correspond to any of the accepted diagnostic categories. However, we question their claims of first description of this tumour type. Differences in nomenclature exist, and the previously published cases of ameloblastoma, ameloblastic fibroma, odontogenic fibroma and odontogenic myxoma are assumed to represent the same pathological process, nine of these accounts actually corresponding to previous descriptions of POT both clinically and pathologically.2–10 Although, at the time, none of these lesions were considered to be a distinct entity, odontogenic myxofibromas coated by a single layer of enamel epithelium have long been well known (References S1). Bernier,11 Tiecke12 and Gorlin,13 oral pathologists of great renown, illustrated a tumour compatible with POT in their seminal publications written approximately half a century ago. We understand that Mosqueda-Taylor et al.1 did not take into account the above reports because some of them were not indexed in PubMed, and their pathological repertoire did not include a superficial smattering of Japanese. Considering that six cases have been reported from Latin America1 and at least five from Japan,5,6,8–10 more examples of this type of tumour might be found in the local domestic scientific literature worldwide (References S1 and S2). Thus POT, previously unrecognized by Mosqueda-Taylor et al.1, may not be as rare as the authors suggest. At present, it is reasonable to consider that POT may arise during the course of embryonic, fetal or early postnatal development, not because of its marked structural resemblance to primitive dental tissues (papilla and follicle) but because of its usual association with anomalies of dental development, including
missing, malformed or unerupted teeth and its limited period of onset before adult life. It may well be that the surface enamel epithelium of POT often invaginates into the mesenchymal component in a manner and pattern reminiscent of normal odontogenesis, leading to its characteristic multilobulated configuration.1–8,10 Such a continuous double epithelial layer is occasionally expanded at the free end to form a microcystic space.1,2,5,7,8,10 Also of note is the presence of several fragments of fibrous tumour lacking a surface epithelial lining.4,6,8 Other examples of this histogenetic interest are dentigerous ameloblastic fibroma and odontogenic fibroma with sparse epithelial strands along the periphery of the tumour (References S3). In summary, there are two tumour mesenchymal patterns of POT, cell-rich (ameloblastic fibromalike)1–3,5,7,8,10 and cell-poor (odontogenic fibromyxoma-like) types.1,4,6,9 Accordingly, some doubt exists as to the exact nature of POT and whether it is truly a newly recognized embryonal tumour of immature dental tissues exhibiting the neoplastic characteristic of progressive growth, or whether it is merely a particular subset (architectural morphological variant) of ameloblastic fibroma or odontogenic fibroma/myxoma of dentigerous type arising during active dental development. Moreover, consideration should be given to the possibility that the cell-rich type may represent the primitive stage of a developing ameloblastic fibroma. The unique combination of proliferating fibrous and covering epithelial elements, a key diagnostic feature,1 accounts for the biphasic growth pattern of POT, thus leaving its ectomesenchymal or mixed epithelial– ectomesenchymal origin an open question.
Conflicts of interest No authors have any relevant financial disclosures or conflict of interest. Fumio Ide Kentaro Kikuchi Kaoru Kusama Takashi Muramatsu1 Division of Oral Pathology, Department of Diagnostic and Therapeutic Sciences, Meikai University School of Dentistry, Saitama, Japan, and 1Department of Endodontics and Clinical Cariology, Tokyo Dental College, Tokyo, Japan
604
Correspondence
1. Mosqueda-Taylor A, Pires FR, Aguirre-Urizar JM et al. Primordial odontogenic tumour: clinico-pathologic analysis of six cases of a previously undescribed entity. Histopathology 2014; 65; 606–612. 2. Hunter HA, Nikiforuk G. Ameloblastoma in a 3-year-old boy. Oral Surg. Oral Med. Oral Pathol. 1954; 7; 906–909. 3. MacLennan WD, McKendrick AJW. Unusual odontogenic tumor: report of case. J. Oral Surg. Anesth. Hosp. Dent. Serv. 1963; 21; 429–431. 4. Main DMG. Fibroma of the mandible. Br. J. Oral Surg. 1965; 3; 172–176. 5. Tomita K, Kawamura M, Fujimori T et al. A case of ameloblastic fibroma arising in the maxilla [Japanese abstract]. Jpn J. Oral Surg. 1972; 18; 653. 6. Inoue Y, Ishikawa K, Jinno T et al. A case of odontogenic myxofibroma [Japanese with English abstract]. Aichi-Gakuin J. Dent. Sci. 1979; 17; 87–93. 7. Meyers AD, Poulson T, Pettigrew J, Clark M. Cystic ameloblastic fibroma. Ear Nose Throat J. 1991; 70; 729–732. 8. Sakaki T, Kaji R, Wato M, Miyagawa T, Otake S, Mushimoto K. A segmental ameloblastic fibroma in the maxilla [Japanese with English abstract]. Jpn J. Oral Maxillofac. Surg. 1993; 39; 481–483. 9. Morita S, Jogetsu K, Nosaka Y, Tsunokuma M, Akane M, Okano H. A case of odontogenic fibroma in the mandible of a three-year-old boy [Japanese with English abstract]. Jpn J. Oral Maxillofac. Surg. 1994; 40; 935–937. 10. Semba I. Histological classification of odontogenic tumors and cysts [Japanese with English abstract]. Dent. Radiol. 1996; 36; 137–152. 11. Bernier JL. Odontogenic tumors. NY State. Dent. J. 1947; 13; 560–567. 12. Tiecke RW, Stuteville OH, Calandra JC eds. Pathologic physiology of oral disease. St Louis: CV Mosby, 1959; 312–313. 13. Gorlin RJ, Chaudhry AP, Pindborg JJ. Odontogenic tumors. Classification, histopathology, and clinical behavior in man and domesticated animals. Cancer 1961; 14; 73–101.
Supporting Information Additional Supporting Information may be found in the online version of this article: References S1. Odontogenic fibroma with a superficial covering of enamel epithelium. References S2. Odontogenic myxoma surfaced by other types of epithelium. References S3. Dentigerous ameloblastic fibroma or odontogenic fibroma with large areas devoid of epithelium.
Reply: Primordial odontogenic tumour: it is truly novel DOI: 10.1111/his.12605 © 2014 John Wiley & Sons Ltd
Sir: We would like to thank Ide et al.1 for their comments, interest and collaboration to obtain a better
understanding of the recently reported primordial odontogenic tumour (POT). We apologize for not reading Japanese but, as English is the main scientific international language, PubMed/MEDLINE represents the world reference for searching peer-reviewed scientific literature in medicine. In our article,2 we presented a series of six tumours sharing clinical, radiographic and microscopic findings that allowed us to consider them to be a specific entity that had not been previously described. The cases were collected from diverse geographical areas according to the origin of the authors, including Latin America and Europe (Spain). As Ide et al.1 pointed out, there may be, as may have occurred with several other entities when first reported, the possibility of some isolated cases of odontogenic tumours with findings similar to POT reported in old literature and/or in languages different to English, but, unfortunately, such cases were not highlighted and recognized as a distinct or specific entity. On the contrary, the cases that they claim as possible POT were considered to be examples of well-recognized odontogenic tumours such as ameloblastoma, myxofibroma, ameloblastic fibroma, or odontogenic fibroma. Assuming that some of these cases could be classified (after our definition of POT) as examples of this novel entity, which is very difficult to confirm by just reading the publications in which references are made to the existence of odontogenic fibroma, ameloblastic fibroma, or a myxofibroma partly coated by a single layer of odontogenic epithelium (which may occur when these lesions are fused to a dental follicle or by tangenctial sectioning), or when an ameloblastic fibroma is located in a dentigerous relationship, it would be interesting to consider them as an important part of the history of this entity, supporting the acceptance of this lesion as a new odontogenic tumour. The citations in which Ide et al.1 claim to find cases of POT refer mainly to Japanese reports and old articles and textbooks, which used terms such as ‘ameloblastoma’, ‘ameloblastic fibroma’, ‘odontogenic myxofibroma’, ‘cystic ameloblastic fibroma’, and ‘odontogenic fibroma’, which are entities that have been properly discussed as differential diagnoses of POT in our article,2 in which we emphasize those aspects that allow their differentiation from this tumour. In our study, special care was taken to discard ameloblastic fibroma, odontogenic fibroma and myxoma, based on findings previously described by other authors3 and studied and published by our own group.4,5 Histopathology, 66, 603–612.
Copyright of Histopathology is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use.
