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Peripheral ameloblastoma
110
J. Cranio-Max.-Fac. Surg. 15 (1987)
J. Cranio-Max.-Fac. Surg. t5 (1987) 110-112 © Georg Thieme Verlag Stuttgart • New York
Peripheral Ameloblastoma A Case Report Giuseppe Ficarra, Louis S. Hansen Division of Oral Pathology (Head: L. S. Hansen, D.D.S., M.S., M.B.A.), School of Dentistry, University of California, San Francisco, USA. Submitted 28.1. 1986; accepted 1.5. 1986
Summary The peripheral or extraosseous ameloblastoma is a rare tumour of the oral cavity. Only a few well-documented cases have been reported. One additional case of this infrequent tumour in a 70-year-old edentulous man is described. The tumour arose on the mucosa of the lower alveolar crest. It was asymptomatic tender, with a raised and red appearance. The tumour was excised and no evidence of recurrence was seen five years later. Peripheral ameloblastoma probably arises from oral mucosa or from cell rests. It is less invasive than its intraosseous counterpart, and surgical excision with adequate margins is the treatment of choice.
Key-Words Introduction
Jaw tumour - Peripheral ameloblastoma - Ameloblas-
The peripheral amelobiastoma is a very rare odontogenic tumour (Gardner, 1977; Shafer et al., 1983; Lucas, 1984). It was first described by Stanley and Krogh (1959) who reported clinical and histological evidence of an ameloblastoma occurring in the soft tissues of the molar area of the mandible. Subsequently, more cases have been reported in the oral mucosa and gingiva (RusseI, 1966; Klinar and McManis, 1969; Lee et al., 1970; Frankel et al., 1977; Gardner, 1977; Wesley et al., 1977; Greer and Hammond, 1978; Gould et at., 1982; Moskow and Baden, 1982; GuraInick et al., 1983; Ide et al., 1983; Patrikiou et al., 1983; Schaberg et al., 1983; Shiba et al., 1983; Connolly et al., 1984; Anneroth and Johansson, 1985; Ramnarayan et al., 1985). The peripheral ameloblastoma is described as a neoplasm arising in soft tissue overlying tooth-bearing regions, not including the buccal mucosa, the lips or the cranio-pharyngeal regions (Lucas, 1984). However, ameloblastoma arising in buccat mucosa has been described in two papers (Braunstein, 1949; Klinar and McManis, 1969). It is generally accepted that peripheral ameloblastoma arises from the basal cells of the oral mucosa or from remnants of the dental lamina (rests of Serres) (Russel, 1966; Gardner, 1977; Wesley et al., 1977; Lucas, !984). It is our purpose to report an additional example of a peripheral ameloblastoma and to review the literature regarding the biological behaviour and histogenesis of this neoplastic entity.
toma.
Case report A 70-year-old Caucasian man presented to his dentist with a raised, tender, friable mass on the edentulous right lower alveolar crest. The lesion had been present for 4 to 5 months, and except for the tenderness was asymptomatic. The clinical diagnosis was irritation fibroma. After surgical excision, the tissue was fixed in 10 % buffered formalin and submitted for histopathological evaluation. The microscopic examination revealed sections of soft tissue composed of a superficial proliferation of epithelial cells arising from atrophic overlying surface epithelium, surrounded by mature fibrovascular connective tissue (Fig. 1). In the central portion of the specimen, the epithdium was prominently atrophic and gave rise to several variouslysized and irregularly shaped islands of epithelium which were characterized by peripherally-located cuboidal-to-
low-columnar cells with palisading and polarization of spindle-shaped-to-oval nuclei (Fig. 2). In the central area there was a loose-to-compact arrangement of squamoid epithelial cells with occasional keratin formation. Individual islands were sometimes attached to the basilar layer of the overlying epithelium (Fig. 3). The supporting connective tissues exhibited mild chronic inflammation, which was more intense around the superficial epithelial proliferation. In addition, there were occasional fragments of calcification in the connective tissues. The final diagnosis was peripheral ameloblastoma of the right mandibular alveolar mucosa. Since the operation the patient has had several follow-up examinations. No evidence of disease could be seen clinically or radiographically five years later.
Discussion The histogenesis of the peripheral ameloblastoma is controversial and has been debated by many authors (Russel, 1966; Gardner, 1977; Wesley et al., 1977; Lucas, 1984). The possible origin of these tumours is the oral mucosa or cell rests (Lucas, 1984). WesIeyet al. (1977) support the theory that peripheral ameloblastoma develops from remnants of the dental lamina and its enamel organ derivatives, because often the turnout is separated from the overlying surface epithelium by fibrous connective tissue. However, in many cases, as in our case, there is an epithelial continuity between the tumour and the basal epithelial cells that can be detected in serial sections (Fig. 3), supporting the idea that peripheral ameloblastoma arises from the basal cell layer of the oral mucosa (Russel, 1966; Lucas, 1984). An alternative explanation for this continuity may be secondary involvement of the overlying mucosa by the peripherally enlarging turnout (Wesley et al., 1977). Unfortunately, the ultrastructural features of the peripheral ameloblastoma have failed to clarify the histogenesis of this tumour (Greer and Hammond, 1978; Gould et al., 1982). Whereas intraosseous ameloblastoma is a relatively common neoplasm (1% of all oral tumours), it is a rare event to
Peripheral Ameloblastoma
J. Cranio-Max.-Fac. Surg. 15 (1987)
111
Fig. 1 Peripheral ameloblastoma: islands and nests of tumour epithelium lying in a connective tissue stroma. (Haematoxylin and Eosin stain. Magnification, x 10),
Fig. 2 An island of tumour epithelium exhibiting a peripheral row of tall palisading cells and central squamoid metaplasia. (Haematoxylin and Eosin stain. Magnification, x 100).
observe its peripheral or extraosseous counterpart. Three recent reports (Moskow et al., 1982; Patrikiou et al., 1983; Shiba et al., 1983) have exhaustively reviewed the literature on the subject. Shiba et al. (1983) recently reviewed 26 cases of peripheral ameloblastomas from the literature and added one of their own. In their review they found a male predilection and the age of the patients, at the time of diagnosis, ranged from 23 to 82 years, with a mean of 50 years. There was a slight preference for the lower jaw, especially the premolar area. Recurrences were rare and comparison with the clinical behaviour of intraosseous ameloblastoma revealed appreciable differences. They concluded that peripheral ameloblastoma develops later in life, grows slowly and only requires conservative surgical treatment. Intraosseous ameloblastoma is locally invasive but rarely, if ever, leads to metastasis (Small and Waldron, 1955). The peripheral ameloblastoma is less invasive than the intraosseous counterpart and does not require aggressive treatment (Gardner, 1977; Lucas, 1984). Surgical excisiol) with adequate margins is the treatment of choice and recurrences are extremely rare. The peripheral ameloblastoma must be differentiated from the peripheral odontogenic fibroma (WHO type) or "Baden
tumour" and from the basal cell carcinoma of the gingiva. The peripheral odontogenic fibroma (WHO type) is characterized by small islands of odontogenic epithelium embedded in fibrous connective tissue. The basal cell layer does not show hyperchromatism, intracytoplasmic vacuoles or polarization of the nuclei away from the basement membrane as are observed in the peripheral ameloblastoma (Baden et al., 1968; Gardner, 1977, 1982). Concerning basal cell carcinoma of the gingiva, a comparison between this lesion and the peripheral ameloblastoma was made by Simpson (1974) and Greer and Hammond (1978). The nuclear polarization and the sharp demarcation between the peripheral columnar and the central reticular cells are distinctive features of peripheral ameloblastoma. Nevertheless, Gardner (1977) considered these two lesions to be indistinguishable. The peripheral ameloblastoma should also be differentiated from the squamous odontogenic tumour. The latter is composed of islands of mature squamous epithelium without peripheral palisaded or polarized columnar cells. The squamous cells are uniform and exhibit no pleomorphism, nuclear hyperchromatism or mitotic figures (Goldblatt et al., 1982; Monteil and Terestri, 1985). Other odontogenic tumours occur occasionally in the gingi-
112
J. Cranio-Max.-Fac. Surg. i5 (1987)
Fig. 3 Island of amelobiastomatous tissue in continuity with the surface mucosa. (Haematoxylin and Eosin stain. Magnification, x 38).
va as the calcifying epithelial odontogenic tumour, the calcifying odontogenic cyst and the adenomatoid odontogenic tumour (Pindborg, 1966; Freedman et al., 1975; Yazdi and Nowparast, 1974). All these lesions have distinct features which should lead to the correct diagnosis. Because of the rarity of the peripheral ameloblastoma, careful attention to the clinical presentation and histopathological features should be paid to ensure accurate diagnosis, treatment and follow-up of the tumour. Acknowledgement This study was supported in part by a grant from the Donald T. Elliott, Oral Cancer Research Fund. The authors thank Evangeline Leash for her editorial assistance.
G. Ficarra, L. S. Hansen: Peripheral Ameloblastoma Connolly, S. F., S. Sonis, P. B. Lockhart: An usually located early peripheral ameloblastoma. J. Oral Med. 39 (1984) 180 Frankel, K. A., J. D. Smith, L. S. Frankel: Soft tissue ameloblastoma in a 92-year-old woman. Arch. Otolaryngol. 103 (1977) 499 Freedman, P. D., H. Lumerman, J. K. Gee: Calcifying odontogenic cyst. A review and analysis of seventy cases. Oral Snrg. 40 (1975) 93 Gardner, D. G.: Peripheral ameloblastoma. Cancer 39 (1977) 1625 Gardner, D. G.: The peripheral odontogenic fibroma: An attempt at clarification. Oral Snrg. 54 (1982) 40 Goldblatt, L. I., R. B. Brannon, G. L. Ellis: Squamous odontogenic tumor. Report of five cases and review of the literature. Oral Surg. 54 (1982) 187 Gould, A. R., A. G. Farman, E. K. Dejean, L. R. Van Arsdall: Peripheral ameloblastoma in an ultrastructural analysis. J. Oral Path. 11 (1982) 90 Greer, R. O., Jr., W. S. Hammond: Extraosseous ameloblastoma: light microscopic and ultrastructural observation. J. Oral Surg. 36 (1978) 553 Guralnick, W., R. Chuong, M. Goodman: Peripheral ameloblastoma of gingiva. J. Oral Maxillofac. Surg. 41 (1983) 536 Ide, F:, I. Saito, S. Umemura: Peripheral ameloblastoma: a case report. J. Periodontol. 54 (1983) 173 Klinar, K. L., J. C. McManis: Soft tissue ameloblastomas. Report of a case. Oral Surg. 28 (1969) 266 Lee, K. W., T. C. Chin, G. Paul: Peripheral ameloblastoma. Br. J. Oral Surg. 8 (1970) 150 Lucas, R. B.: Pathology of Tumours of the Oral Tissues. 4th Ed., Churchill Livingstone, London (1984) 36 Monteil, R. A., P. Terestri: Squamous odontogenic tumor related to an unerupted lower canine. J. Oral Maxiltofac. Surg. 43 (1985) 888 Moskow, B. S., E. Baden: The peripheral ameloblastoma of the gingiva. J. Periodontol. 53 (1982) 736 Patrikiou, A., S. Papanicolau, E. Stylogianni, S. Sotiriadou: Peripheral ameloblastoma. Case report and review of the literature. Int. J. Oral Surg. 12 (1983) 51 Pindhorg, J. J.: The calcifying epithelial odontogenic tumor. Review of literature and report of an extraosseous case. Acta Odontol. Scand. 24 (1966) 419 Ramnarayan, K., R. G. Nayak, A. G. Kavalam: Peripheral ameloblastoma. Int. J. Oral Surg. 14 (1985) 300 Russel, A.: Ameloblastoma of mucosal origin. NZ Dent. J. 62 (1966) 116 Schaberg, S. J., R. F. Antimarino, G. L. Pierce, B. E. Crawford: Peripheral ameloblastoma. Report of a case. Int. J. Oral Surg. 12 (1983) 344 Shafer, W. G., K. M. Hine, B. M. Levy, C. E. Tomich: A Textbook of Oral Pathology. 4 ~ Ed., W. B. Sannders Company, Philadelphia, London (1983) 276 Shiba, R., S. Sakoda, N. Yamada: Peripheral ameloblastoma. J. Oral Maxillofac. Surg. 41 (1983) 460 Simpson, H. E.: Basal-cell carcinoma and peripheral ameloblastoma. Oral Surg. 38 (1974) 233 Small, I. A., C. A. Waldron: Ameloblastoma of the jaws. Oral Surg. 8 (1955) 281 Stanley, H. R., H. V. Krogh: Peripheral ameloblastoma. Report of a case. Oral Surg. 12 (1959) 760 Wesley, R., E. Barninski, S. Mintz: Peripheral ameloblastoma: report of a case and review of the literature. J. Oral Surg. 35 (1977) 670 Yazdi, 1., B. Nowparast: Extraosseous adenomatoid odontogenic tumor with special reference to the probability of the basal-cell layer of oral epithelium as a potential source of origin. Oral Surg. 37 (1974) 249
References
Anneroth, G., B. Johansson: Peripheral ameloblastoma. Int. J. Oral Surg. 14 (1985) 295 Baden, E., B. S. Moskow, R. Moskow: Odontogenic gingival epithelial hamartoma. J. Oral Surg. 26 (1968) 702 Braunstein, E.: Case report of an extraosseous adamantinoblastoma. Oral Surg. 2 (1949) 726
L. S. Hansen, D.D.S. Division of Oral Pathology Rm. S-524 School of Dentistry University of California San Francisco, CA 94143-0424
J. Cranio-Max.-Fac. Surg. 15 (1987)
J. Cranio-Max.-Fac. Surg. t5 (1987) 110-112 © Georg Thieme Verlag Stuttgart • New York
Peripheral Ameloblastoma A Case Report Giuseppe Ficarra, Louis S. Hansen Division of Oral Pathology (Head: L. S. Hansen, D.D.S., M.S., M.B.A.), School of Dentistry, University of California, San Francisco, USA. Submitted 28.1. 1986; accepted 1.5. 1986
Summary The peripheral or extraosseous ameloblastoma is a rare tumour of the oral cavity. Only a few well-documented cases have been reported. One additional case of this infrequent tumour in a 70-year-old edentulous man is described. The tumour arose on the mucosa of the lower alveolar crest. It was asymptomatic tender, with a raised and red appearance. The tumour was excised and no evidence of recurrence was seen five years later. Peripheral ameloblastoma probably arises from oral mucosa or from cell rests. It is less invasive than its intraosseous counterpart, and surgical excision with adequate margins is the treatment of choice.
Key-Words Introduction
Jaw tumour - Peripheral ameloblastoma - Ameloblas-
The peripheral amelobiastoma is a very rare odontogenic tumour (Gardner, 1977; Shafer et al., 1983; Lucas, 1984). It was first described by Stanley and Krogh (1959) who reported clinical and histological evidence of an ameloblastoma occurring in the soft tissues of the molar area of the mandible. Subsequently, more cases have been reported in the oral mucosa and gingiva (RusseI, 1966; Klinar and McManis, 1969; Lee et al., 1970; Frankel et al., 1977; Gardner, 1977; Wesley et al., 1977; Greer and Hammond, 1978; Gould et at., 1982; Moskow and Baden, 1982; GuraInick et al., 1983; Ide et al., 1983; Patrikiou et al., 1983; Schaberg et al., 1983; Shiba et al., 1983; Connolly et al., 1984; Anneroth and Johansson, 1985; Ramnarayan et al., 1985). The peripheral ameloblastoma is described as a neoplasm arising in soft tissue overlying tooth-bearing regions, not including the buccal mucosa, the lips or the cranio-pharyngeal regions (Lucas, 1984). However, ameloblastoma arising in buccat mucosa has been described in two papers (Braunstein, 1949; Klinar and McManis, 1969). It is generally accepted that peripheral ameloblastoma arises from the basal cells of the oral mucosa or from remnants of the dental lamina (rests of Serres) (Russel, 1966; Gardner, 1977; Wesley et al., 1977; Lucas, !984). It is our purpose to report an additional example of a peripheral ameloblastoma and to review the literature regarding the biological behaviour and histogenesis of this neoplastic entity.
toma.
Case report A 70-year-old Caucasian man presented to his dentist with a raised, tender, friable mass on the edentulous right lower alveolar crest. The lesion had been present for 4 to 5 months, and except for the tenderness was asymptomatic. The clinical diagnosis was irritation fibroma. After surgical excision, the tissue was fixed in 10 % buffered formalin and submitted for histopathological evaluation. The microscopic examination revealed sections of soft tissue composed of a superficial proliferation of epithelial cells arising from atrophic overlying surface epithelium, surrounded by mature fibrovascular connective tissue (Fig. 1). In the central portion of the specimen, the epithdium was prominently atrophic and gave rise to several variouslysized and irregularly shaped islands of epithelium which were characterized by peripherally-located cuboidal-to-
low-columnar cells with palisading and polarization of spindle-shaped-to-oval nuclei (Fig. 2). In the central area there was a loose-to-compact arrangement of squamoid epithelial cells with occasional keratin formation. Individual islands were sometimes attached to the basilar layer of the overlying epithelium (Fig. 3). The supporting connective tissues exhibited mild chronic inflammation, which was more intense around the superficial epithelial proliferation. In addition, there were occasional fragments of calcification in the connective tissues. The final diagnosis was peripheral ameloblastoma of the right mandibular alveolar mucosa. Since the operation the patient has had several follow-up examinations. No evidence of disease could be seen clinically or radiographically five years later.
Discussion The histogenesis of the peripheral ameloblastoma is controversial and has been debated by many authors (Russel, 1966; Gardner, 1977; Wesley et al., 1977; Lucas, 1984). The possible origin of these tumours is the oral mucosa or cell rests (Lucas, 1984). WesIeyet al. (1977) support the theory that peripheral ameloblastoma develops from remnants of the dental lamina and its enamel organ derivatives, because often the turnout is separated from the overlying surface epithelium by fibrous connective tissue. However, in many cases, as in our case, there is an epithelial continuity between the tumour and the basal epithelial cells that can be detected in serial sections (Fig. 3), supporting the idea that peripheral ameloblastoma arises from the basal cell layer of the oral mucosa (Russel, 1966; Lucas, 1984). An alternative explanation for this continuity may be secondary involvement of the overlying mucosa by the peripherally enlarging turnout (Wesley et al., 1977). Unfortunately, the ultrastructural features of the peripheral ameloblastoma have failed to clarify the histogenesis of this tumour (Greer and Hammond, 1978; Gould et al., 1982). Whereas intraosseous ameloblastoma is a relatively common neoplasm (1% of all oral tumours), it is a rare event to
Peripheral Ameloblastoma
J. Cranio-Max.-Fac. Surg. 15 (1987)
111
Fig. 1 Peripheral ameloblastoma: islands and nests of tumour epithelium lying in a connective tissue stroma. (Haematoxylin and Eosin stain. Magnification, x 10),
Fig. 2 An island of tumour epithelium exhibiting a peripheral row of tall palisading cells and central squamoid metaplasia. (Haematoxylin and Eosin stain. Magnification, x 100).
observe its peripheral or extraosseous counterpart. Three recent reports (Moskow et al., 1982; Patrikiou et al., 1983; Shiba et al., 1983) have exhaustively reviewed the literature on the subject. Shiba et al. (1983) recently reviewed 26 cases of peripheral ameloblastomas from the literature and added one of their own. In their review they found a male predilection and the age of the patients, at the time of diagnosis, ranged from 23 to 82 years, with a mean of 50 years. There was a slight preference for the lower jaw, especially the premolar area. Recurrences were rare and comparison with the clinical behaviour of intraosseous ameloblastoma revealed appreciable differences. They concluded that peripheral ameloblastoma develops later in life, grows slowly and only requires conservative surgical treatment. Intraosseous ameloblastoma is locally invasive but rarely, if ever, leads to metastasis (Small and Waldron, 1955). The peripheral ameloblastoma is less invasive than the intraosseous counterpart and does not require aggressive treatment (Gardner, 1977; Lucas, 1984). Surgical excisiol) with adequate margins is the treatment of choice and recurrences are extremely rare. The peripheral ameloblastoma must be differentiated from the peripheral odontogenic fibroma (WHO type) or "Baden
tumour" and from the basal cell carcinoma of the gingiva. The peripheral odontogenic fibroma (WHO type) is characterized by small islands of odontogenic epithelium embedded in fibrous connective tissue. The basal cell layer does not show hyperchromatism, intracytoplasmic vacuoles or polarization of the nuclei away from the basement membrane as are observed in the peripheral ameloblastoma (Baden et al., 1968; Gardner, 1977, 1982). Concerning basal cell carcinoma of the gingiva, a comparison between this lesion and the peripheral ameloblastoma was made by Simpson (1974) and Greer and Hammond (1978). The nuclear polarization and the sharp demarcation between the peripheral columnar and the central reticular cells are distinctive features of peripheral ameloblastoma. Nevertheless, Gardner (1977) considered these two lesions to be indistinguishable. The peripheral ameloblastoma should also be differentiated from the squamous odontogenic tumour. The latter is composed of islands of mature squamous epithelium without peripheral palisaded or polarized columnar cells. The squamous cells are uniform and exhibit no pleomorphism, nuclear hyperchromatism or mitotic figures (Goldblatt et al., 1982; Monteil and Terestri, 1985). Other odontogenic tumours occur occasionally in the gingi-
112
J. Cranio-Max.-Fac. Surg. i5 (1987)
Fig. 3 Island of amelobiastomatous tissue in continuity with the surface mucosa. (Haematoxylin and Eosin stain. Magnification, x 38).
va as the calcifying epithelial odontogenic tumour, the calcifying odontogenic cyst and the adenomatoid odontogenic tumour (Pindborg, 1966; Freedman et al., 1975; Yazdi and Nowparast, 1974). All these lesions have distinct features which should lead to the correct diagnosis. Because of the rarity of the peripheral ameloblastoma, careful attention to the clinical presentation and histopathological features should be paid to ensure accurate diagnosis, treatment and follow-up of the tumour. Acknowledgement This study was supported in part by a grant from the Donald T. Elliott, Oral Cancer Research Fund. The authors thank Evangeline Leash for her editorial assistance.
G. Ficarra, L. S. Hansen: Peripheral Ameloblastoma Connolly, S. F., S. Sonis, P. B. Lockhart: An usually located early peripheral ameloblastoma. J. Oral Med. 39 (1984) 180 Frankel, K. A., J. D. Smith, L. S. Frankel: Soft tissue ameloblastoma in a 92-year-old woman. Arch. Otolaryngol. 103 (1977) 499 Freedman, P. D., H. Lumerman, J. K. Gee: Calcifying odontogenic cyst. A review and analysis of seventy cases. Oral Snrg. 40 (1975) 93 Gardner, D. G.: Peripheral ameloblastoma. Cancer 39 (1977) 1625 Gardner, D. G.: The peripheral odontogenic fibroma: An attempt at clarification. Oral Snrg. 54 (1982) 40 Goldblatt, L. I., R. B. Brannon, G. L. Ellis: Squamous odontogenic tumor. Report of five cases and review of the literature. Oral Surg. 54 (1982) 187 Gould, A. R., A. G. Farman, E. K. Dejean, L. R. Van Arsdall: Peripheral ameloblastoma in an ultrastructural analysis. J. Oral Path. 11 (1982) 90 Greer, R. O., Jr., W. S. Hammond: Extraosseous ameloblastoma: light microscopic and ultrastructural observation. J. Oral Surg. 36 (1978) 553 Guralnick, W., R. Chuong, M. Goodman: Peripheral ameloblastoma of gingiva. J. Oral Maxillofac. Surg. 41 (1983) 536 Ide, F:, I. Saito, S. Umemura: Peripheral ameloblastoma: a case report. J. Periodontol. 54 (1983) 173 Klinar, K. L., J. C. McManis: Soft tissue ameloblastomas. Report of a case. Oral Surg. 28 (1969) 266 Lee, K. W., T. C. Chin, G. Paul: Peripheral ameloblastoma. Br. J. Oral Surg. 8 (1970) 150 Lucas, R. B.: Pathology of Tumours of the Oral Tissues. 4th Ed., Churchill Livingstone, London (1984) 36 Monteil, R. A., P. Terestri: Squamous odontogenic tumor related to an unerupted lower canine. J. Oral Maxiltofac. Surg. 43 (1985) 888 Moskow, B. S., E. Baden: The peripheral ameloblastoma of the gingiva. J. Periodontol. 53 (1982) 736 Patrikiou, A., S. Papanicolau, E. Stylogianni, S. Sotiriadou: Peripheral ameloblastoma. Case report and review of the literature. Int. J. Oral Surg. 12 (1983) 51 Pindhorg, J. J.: The calcifying epithelial odontogenic tumor. Review of literature and report of an extraosseous case. Acta Odontol. Scand. 24 (1966) 419 Ramnarayan, K., R. G. Nayak, A. G. Kavalam: Peripheral ameloblastoma. Int. J. Oral Surg. 14 (1985) 300 Russel, A.: Ameloblastoma of mucosal origin. NZ Dent. J. 62 (1966) 116 Schaberg, S. J., R. F. Antimarino, G. L. Pierce, B. E. Crawford: Peripheral ameloblastoma. Report of a case. Int. J. Oral Surg. 12 (1983) 344 Shafer, W. G., K. M. Hine, B. M. Levy, C. E. Tomich: A Textbook of Oral Pathology. 4 ~ Ed., W. B. Sannders Company, Philadelphia, London (1983) 276 Shiba, R., S. Sakoda, N. Yamada: Peripheral ameloblastoma. J. Oral Maxillofac. Surg. 41 (1983) 460 Simpson, H. E.: Basal-cell carcinoma and peripheral ameloblastoma. Oral Surg. 38 (1974) 233 Small, I. A., C. A. Waldron: Ameloblastoma of the jaws. Oral Surg. 8 (1955) 281 Stanley, H. R., H. V. Krogh: Peripheral ameloblastoma. Report of a case. Oral Surg. 12 (1959) 760 Wesley, R., E. Barninski, S. Mintz: Peripheral ameloblastoma: report of a case and review of the literature. J. Oral Surg. 35 (1977) 670 Yazdi, 1., B. Nowparast: Extraosseous adenomatoid odontogenic tumor with special reference to the probability of the basal-cell layer of oral epithelium as a potential source of origin. Oral Surg. 37 (1974) 249
References
Anneroth, G., B. Johansson: Peripheral ameloblastoma. Int. J. Oral Surg. 14 (1985) 295 Baden, E., B. S. Moskow, R. Moskow: Odontogenic gingival epithelial hamartoma. J. Oral Surg. 26 (1968) 702 Braunstein, E.: Case report of an extraosseous adamantinoblastoma. Oral Surg. 2 (1949) 726
L. S. Hansen, D.D.S. Division of Oral Pathology Rm. S-524 School of Dentistry University of California San Francisco, CA 94143-0424