Int. J. Oral Surg. 1976: 5 : 2 4 5 - 2 4 9 (Koy words: ameloblastoma; tumors, odontogenic; jaws)
A case report of keratoameloblastoma R. LURIE, M. ALTINI AND M. SHEAR Department oJ Oral Pathology, School o/Pathology, University o/ the Witwatersrand and South African Institute for Medical Research
ABSTIt.ACT In the "WHO histological typing of odontogenic tumours, jaw cysts and allied lesions", the authors recognize five distinct histologic types of ameloblastoma. A further histologic variant, the keratoameloblastoma, was first described by PIm)BOROL A second case of a keratoameloblastoma is reported. This lesion occurred in the maxilla of a 28-year-old Caucasian male. - -
(Received ]or publication 4 April, accepted 5 June 1976)
"The ameloblastoma is a true neoplasm of enamel organ-type tissue which does not undergo differentiation to the point of enamel formation"L It is a benign tumor in the sense that it does not give rise to metastases except in those few cases which undergo malignant transformation. It is locally invasive and therefore difficult to eliminate. Analyses of over 1000 cases showed that ameloblastomas comprised about 1 % of tumors and cysts of the jaws 10. A similar study carried out on the material in our department indicated that 2.3 % of the jaw cysts and tumors accessioned were ameloblastomas 5. In both studies it was found that the ameloblastoma most commonly occurs in the 20-40 year age group and arises in the mandible in the majority of cases. The histologle pattern of the ameloblastoma varies considerably and the WHO Committee on the Histological Typing of Odontogenic Tumours, Jaw Cysts and A1lied LesionsT has described the following
patterns: follicular, plexiform, acanthomatous, basal cell, and granular ceil. In 1970, P~I)BORC described an unusual type of ameloblastoma consisting partly of keratinizing cysts and partly of tumor islands with papilliferous appearance. He suggested that the term papilliferous keratoameloblastoma might be appropriate to describe this lesion. In a search of the literature we were unable to find any other reported cases of this kind. The purpose of our paper is to report a case with very similar histological features to that of PINDBORe'S keratoameloblastoma.
Case report A 28-year-old Caucasian male went to his denfist in Zambia for a routine visit, in the course of which he mentioned a swelling in the maxillary right incisor and canine regions. The swelling had not been painful and was hard until 2 weeks before his appointment, when he noticed, that it had softened. When the dentist had completed his clinical examination an
246
LUR1E, A L T I N [ A N D S H E A R
Fig. 1. Occlusal p l a n e radiograph showing irregular multilocular radiolucent area in right anterior region of maxilla. occlusal r a d i o g r a p h was taken (Fig. 1). A biopsy was p e r f o r m e d and the specimen was s u b m i t t e d to our d e p a r t m e n t for histologic examination. A provisional diagnosis of kera-
toameloblastoma was made. The patient was then referred for further investigation and treatment. E x a m i n a t i o n revealed a swelling of the right maxilla in the nasolabial regfon with obliteration of the fold. The swelling was n o t painful and h a d not increased in size since its initial discovery. T h e r e was no anesthesia over the distribution of the infraorbital nerve and no functional impairment. On palpation the lesion appeared to extend upwards along the lateral aspect of the nose. Intraorally, an ill-defined spongy swelling occupied the labial sulcus between the right maxillary incisor and canine teeth a n d there was a n associated expansion of the palatal alveolus. A vertical surgical scar, resulting from the biopsy, was present over the maxillary right lateral incisor tooth. The maxillary right second p r e m o l a r was absent. All the teeth on the involved side gave positive responses to vitality testing and n o n e of the teeth was mobile or sensitive to percussion. Full blood count, hemoglobin, urea, and electrolyte investigations were all within normal limits. T h e serum calcium and phosphorus levels were also normal. RADIOGRAPHIC FEATURES The occlusal radiograph (Fig. 1) showed an irregular radiolucent area which appeared to
Fig. 2. P a n o r e x r a d i o g r a p h showing well-defined pear-shaped caused divergence of roots of the teeth.
radiolucent area, which has
KE RATOAMELOBLASTOMA be multilocular, extending laterally from the midline of the maxilla to the dental arch and antero-posteriorly from the incisors to the molar region. The panorex radiograph (Fig. 2) and a dental radiograph revealed the presence of an unerupted maxillary right second premolar. A well-defined pear-shaped radiolucent area included the alveolus and maxilla between the maxillary right central incisor and premolar region, producing divergence of the roots of the right maxillary lateral incisor and canine teeth. Some fine trabeculations were observed at the alveolar extremity of the lesion. SURGICAL MANAGEMENT U n d e r nasotracheal anesthesia the tumor area was exposed. A "milky white fluid" was found within the soft tissue. Extensive bone loss had exposed the root surfaces of the right maxillary lateral and canine teeth. The soft tissue lesion extended to the antral and nasal areas. The left maxillary central incisor and maxillary right first molar teeth were extracted. Using a number six fissure bur in a straight dental handpiece a vertical bone cut was made
247
just lateral to the nasal spine down to the left maxillary central incisor socket and a block resection involving the entire tumor area was carried out. The involved mmxillary bone and alveolus were freed and removed. The residual defect was continuous with the maxillary antrum. The postoperative recovery was uneventful. PATHOLOGICAL FEATURES The excised specimen consisted of a portion of the right maxilla with its alveolar and palatal processes, together with the maxillary central, lateral, canine and first premolar teeth. On sectioning the specimen, a multilocular cystic lesion was observed associated with an unerupted maxillary second premolar tooth. Histologic examination showed that the lesion consisted of numerous individual follicles of odontogenic epithelium, many of which had undergone central cystic breakdown to form microeysts of varying size (Fig. 3). T h e cysts were lined by a parakeratinized stratified squnmous epithelium. Some areas of the basal layer consisted of fiat cells with deeply basophilic nuclei. Other areas showed prominent and
Fig. 3. Numerous follicles and cysts lying in fibrous connective tissue stroma. Strands of quiescent odontogenic epithelium (arrowed) can be seen in Stl'oma. H & E • 32.
248
LURIE, ALTINI AND SHEAR in a dense collagenous stroma. Interspersed among the large epithelial masses were smaller loci of quiescent odontogenic epithelium. Numerous loci of dystrophic calcification were present in the stroma lying close to the epithelial follicles (Fig. 5). The larger cystic areas seen in the operation specimen were lined by an irregular parakeratinized stratified squamous epithelium. They were separated from each other by narrow strips of collagenous tissue. The papilliferous projections which PINDBORG described in his case were not a feature of the present tumor. Otherwise, the histologic characteristics are the same.
Fig. 4. Wait of follicle consisting of a single basal layer of cells and parakeratinizing stratified squamous epithelium. Desquamating parakeratinized cells can be seen in lumen of microcyst. H & E, • 100. well-orientated cuboidal ceils with nuclei orientated away from the basement membrane (Fig. 4). In parts, the basal layer showed proliferation and budding. Intracellular edema was a prominent feature of the epithelium. Many of the cyst cavities contained desquamated parakeratotic cells (Figs. 4 & 5). The neoplasm lay
Fig. 5, Typical follicle showing parakeratinized epithelium lining a cyst cavity. Foci of dystrophic calcification are seen in fibrous tissue stroma closely related to basal layer of epithelium. H & E, • 124.
Discussion It has long been felt that the five wellknown histologic varieties of ameloblastoma are only of academic h~terest and that they have no prognostic significance. H A R T M ~ has recently suggested that the granular celt variety may be more aggressive and more prone to recur than the other types following initial conservative therapy. It is felt that the keratoameloblastoma, of which there is only one previously reported caseL should be regarded as an additional histologic variant of this mrnor. T h e site of occurrence of this lesion is tmusual in that while most ameloblastomas occur in the mandible, this lesion occurred in the maxilla. Pn~DBOR&S case occurred in the mandibular right angle of a 57-yearold woman. The radiographic features of this case, while not pathognomonic of an ameloblastoma, were strongly suggestive of this lesion. T h e keratoameloblastoma is a distinct entity and should be distinguished f r o m the acanthomatous variety of ameloblastoma and from the so-called keratinizing ameloblastoma. The latter term has been used 2 to describe what is generally called the calcifying odontogenic cystT, which is sometimes associated with ameloblastoma t, 4, s It is not possible to c o m m e n t on the behavior of the keratoameloblastoma in the
KERATOAMELOBLASTOMA absence of any corresponding data. It was assumed, in deciding on the m a n n e r in which the present case should be treated, that it was unlikely to behave any differently f r o m the other varieties of ameloblastoma. It was therefore treated by wide excision and p r i m a r y closure. Histopathologic examination revealed that all the margins w e r e free of t u m o r and a good prognosis can be anticipated. Acknowledgments - We would like to thank Dr. T. E. REYNOLDS Of Zambia for referring the patient and Dr. I. SMITH, Head of the Department of Maxillo-Facial and Oral Surgery of the Johannesburg General Hospital and University of the Witwatersrand, who was responsible for the surgical management of the case.
References 1. ALTINI, M. & FARMAN, A. G.: The calcifying odontogenic cyst. Eight new cases and a review of the literature. Oral Stirs. 1975: 40: 751-759. 2. BHaSKAR, S. N.: Gingival cyst and the keratinizing ameloblastoma. Oral Surg. 1965: 19: 796-807.
Address: Dr. R. Lurie Department o/ Oral Pathology School o] Dentistry University o] the Witwatersrand Jalz Smuts Avenue Milner Park Johannesburg 2901 South A]rica
249
3. I-IARTM^N, K. S.: Granular cell ameloblastoma - a survey of 20 cases from the Armed Forces 2nstitute of Pathology. Oral Surg. 1974: 38: 241-253. 4. KAWAI, T., 2TO, H., KITAYAMA,S., YAMADA, Y., SASAYA,M. & TOMtTA, R.: A case report of keratinizing and calcifying ameloblastoma. Jap. J. Oral Surg. 1971: 17: 5659. 5. MEER~OTrER, V.: The ameloblastoma in the Witwatersrand area. 4th Proceedings International Academy Oral Pathology 1969, p. 144-156. 6. PINDBORG, J. J.: Pathology o] the dental hard tissues. 1st. Ed. Munksgaard, Copenhagen 2970, p. 371-375. 7. PINDBORG,J. J., KRAMER,2. R. H. & TORLONI, H.: Histological classification o/ odontogenie turnouts, jaw cysts and allied lesions. 1st Ed. WHO, Geneva 1971. 8. PRAETORIUS) F.: Calcifying odontogenic cyst: range variations and neoplastic potential. Int. J. Oral Surg. 2975: 4 : 8 9 (Abstr). 9. SHAFER, W. G., HINE, M. K. & LEVY, B. M.: A textbook o] oral pathology. 3rd Ed. W. B. Saunders Company, Philadelphia 1974. 10. SMALL, I. A. • WALDRON, C. A.: Ameloblastomas of the jaws. Oral Surg. 1965: 8: 281-297.
A case report of keratoameloblastoma R. LURIE, M. ALTINI AND M. SHEAR Department oJ Oral Pathology, School o/Pathology, University o/ the Witwatersrand and South African Institute for Medical Research
ABSTIt.ACT In the "WHO histological typing of odontogenic tumours, jaw cysts and allied lesions", the authors recognize five distinct histologic types of ameloblastoma. A further histologic variant, the keratoameloblastoma, was first described by PIm)BOROL A second case of a keratoameloblastoma is reported. This lesion occurred in the maxilla of a 28-year-old Caucasian male. - -
(Received ]or publication 4 April, accepted 5 June 1976)
"The ameloblastoma is a true neoplasm of enamel organ-type tissue which does not undergo differentiation to the point of enamel formation"L It is a benign tumor in the sense that it does not give rise to metastases except in those few cases which undergo malignant transformation. It is locally invasive and therefore difficult to eliminate. Analyses of over 1000 cases showed that ameloblastomas comprised about 1 % of tumors and cysts of the jaws 10. A similar study carried out on the material in our department indicated that 2.3 % of the jaw cysts and tumors accessioned were ameloblastomas 5. In both studies it was found that the ameloblastoma most commonly occurs in the 20-40 year age group and arises in the mandible in the majority of cases. The histologle pattern of the ameloblastoma varies considerably and the WHO Committee on the Histological Typing of Odontogenic Tumours, Jaw Cysts and A1lied LesionsT has described the following
patterns: follicular, plexiform, acanthomatous, basal cell, and granular ceil. In 1970, P~I)BORC described an unusual type of ameloblastoma consisting partly of keratinizing cysts and partly of tumor islands with papilliferous appearance. He suggested that the term papilliferous keratoameloblastoma might be appropriate to describe this lesion. In a search of the literature we were unable to find any other reported cases of this kind. The purpose of our paper is to report a case with very similar histological features to that of PINDBORe'S keratoameloblastoma.
Case report A 28-year-old Caucasian male went to his denfist in Zambia for a routine visit, in the course of which he mentioned a swelling in the maxillary right incisor and canine regions. The swelling had not been painful and was hard until 2 weeks before his appointment, when he noticed, that it had softened. When the dentist had completed his clinical examination an
246
LUR1E, A L T I N [ A N D S H E A R
Fig. 1. Occlusal p l a n e radiograph showing irregular multilocular radiolucent area in right anterior region of maxilla. occlusal r a d i o g r a p h was taken (Fig. 1). A biopsy was p e r f o r m e d and the specimen was s u b m i t t e d to our d e p a r t m e n t for histologic examination. A provisional diagnosis of kera-
toameloblastoma was made. The patient was then referred for further investigation and treatment. E x a m i n a t i o n revealed a swelling of the right maxilla in the nasolabial regfon with obliteration of the fold. The swelling was n o t painful and h a d not increased in size since its initial discovery. T h e r e was no anesthesia over the distribution of the infraorbital nerve and no functional impairment. On palpation the lesion appeared to extend upwards along the lateral aspect of the nose. Intraorally, an ill-defined spongy swelling occupied the labial sulcus between the right maxillary incisor and canine teeth a n d there was a n associated expansion of the palatal alveolus. A vertical surgical scar, resulting from the biopsy, was present over the maxillary right lateral incisor tooth. The maxillary right second p r e m o l a r was absent. All the teeth on the involved side gave positive responses to vitality testing and n o n e of the teeth was mobile or sensitive to percussion. Full blood count, hemoglobin, urea, and electrolyte investigations were all within normal limits. T h e serum calcium and phosphorus levels were also normal. RADIOGRAPHIC FEATURES The occlusal radiograph (Fig. 1) showed an irregular radiolucent area which appeared to
Fig. 2. P a n o r e x r a d i o g r a p h showing well-defined pear-shaped caused divergence of roots of the teeth.
radiolucent area, which has
KE RATOAMELOBLASTOMA be multilocular, extending laterally from the midline of the maxilla to the dental arch and antero-posteriorly from the incisors to the molar region. The panorex radiograph (Fig. 2) and a dental radiograph revealed the presence of an unerupted maxillary right second premolar. A well-defined pear-shaped radiolucent area included the alveolus and maxilla between the maxillary right central incisor and premolar region, producing divergence of the roots of the right maxillary lateral incisor and canine teeth. Some fine trabeculations were observed at the alveolar extremity of the lesion. SURGICAL MANAGEMENT U n d e r nasotracheal anesthesia the tumor area was exposed. A "milky white fluid" was found within the soft tissue. Extensive bone loss had exposed the root surfaces of the right maxillary lateral and canine teeth. The soft tissue lesion extended to the antral and nasal areas. The left maxillary central incisor and maxillary right first molar teeth were extracted. Using a number six fissure bur in a straight dental handpiece a vertical bone cut was made
247
just lateral to the nasal spine down to the left maxillary central incisor socket and a block resection involving the entire tumor area was carried out. The involved mmxillary bone and alveolus were freed and removed. The residual defect was continuous with the maxillary antrum. The postoperative recovery was uneventful. PATHOLOGICAL FEATURES The excised specimen consisted of a portion of the right maxilla with its alveolar and palatal processes, together with the maxillary central, lateral, canine and first premolar teeth. On sectioning the specimen, a multilocular cystic lesion was observed associated with an unerupted maxillary second premolar tooth. Histologic examination showed that the lesion consisted of numerous individual follicles of odontogenic epithelium, many of which had undergone central cystic breakdown to form microeysts of varying size (Fig. 3). T h e cysts were lined by a parakeratinized stratified squnmous epithelium. Some areas of the basal layer consisted of fiat cells with deeply basophilic nuclei. Other areas showed prominent and
Fig. 3. Numerous follicles and cysts lying in fibrous connective tissue stroma. Strands of quiescent odontogenic epithelium (arrowed) can be seen in Stl'oma. H & E • 32.
248
LURIE, ALTINI AND SHEAR in a dense collagenous stroma. Interspersed among the large epithelial masses were smaller loci of quiescent odontogenic epithelium. Numerous loci of dystrophic calcification were present in the stroma lying close to the epithelial follicles (Fig. 5). The larger cystic areas seen in the operation specimen were lined by an irregular parakeratinized stratified squamous epithelium. They were separated from each other by narrow strips of collagenous tissue. The papilliferous projections which PINDBORG described in his case were not a feature of the present tumor. Otherwise, the histologic characteristics are the same.
Fig. 4. Wait of follicle consisting of a single basal layer of cells and parakeratinizing stratified squamous epithelium. Desquamating parakeratinized cells can be seen in lumen of microcyst. H & E, • 100. well-orientated cuboidal ceils with nuclei orientated away from the basement membrane (Fig. 4). In parts, the basal layer showed proliferation and budding. Intracellular edema was a prominent feature of the epithelium. Many of the cyst cavities contained desquamated parakeratotic cells (Figs. 4 & 5). The neoplasm lay
Fig. 5, Typical follicle showing parakeratinized epithelium lining a cyst cavity. Foci of dystrophic calcification are seen in fibrous tissue stroma closely related to basal layer of epithelium. H & E, • 124.
Discussion It has long been felt that the five wellknown histologic varieties of ameloblastoma are only of academic h~terest and that they have no prognostic significance. H A R T M ~ has recently suggested that the granular celt variety may be more aggressive and more prone to recur than the other types following initial conservative therapy. It is felt that the keratoameloblastoma, of which there is only one previously reported caseL should be regarded as an additional histologic variant of this mrnor. T h e site of occurrence of this lesion is tmusual in that while most ameloblastomas occur in the mandible, this lesion occurred in the maxilla. Pn~DBOR&S case occurred in the mandibular right angle of a 57-yearold woman. The radiographic features of this case, while not pathognomonic of an ameloblastoma, were strongly suggestive of this lesion. T h e keratoameloblastoma is a distinct entity and should be distinguished f r o m the acanthomatous variety of ameloblastoma and from the so-called keratinizing ameloblastoma. The latter term has been used 2 to describe what is generally called the calcifying odontogenic cystT, which is sometimes associated with ameloblastoma t, 4, s It is not possible to c o m m e n t on the behavior of the keratoameloblastoma in the
KERATOAMELOBLASTOMA absence of any corresponding data. It was assumed, in deciding on the m a n n e r in which the present case should be treated, that it was unlikely to behave any differently f r o m the other varieties of ameloblastoma. It was therefore treated by wide excision and p r i m a r y closure. Histopathologic examination revealed that all the margins w e r e free of t u m o r and a good prognosis can be anticipated. Acknowledgments - We would like to thank Dr. T. E. REYNOLDS Of Zambia for referring the patient and Dr. I. SMITH, Head of the Department of Maxillo-Facial and Oral Surgery of the Johannesburg General Hospital and University of the Witwatersrand, who was responsible for the surgical management of the case.
References 1. ALTINI, M. & FARMAN, A. G.: The calcifying odontogenic cyst. Eight new cases and a review of the literature. Oral Stirs. 1975: 40: 751-759. 2. BHaSKAR, S. N.: Gingival cyst and the keratinizing ameloblastoma. Oral Surg. 1965: 19: 796-807.
Address: Dr. R. Lurie Department o/ Oral Pathology School o] Dentistry University o] the Witwatersrand Jalz Smuts Avenue Milner Park Johannesburg 2901 South A]rica
249
3. I-IARTM^N, K. S.: Granular cell ameloblastoma - a survey of 20 cases from the Armed Forces 2nstitute of Pathology. Oral Surg. 1974: 38: 241-253. 4. KAWAI, T., 2TO, H., KITAYAMA,S., YAMADA, Y., SASAYA,M. & TOMtTA, R.: A case report of keratinizing and calcifying ameloblastoma. Jap. J. Oral Surg. 1971: 17: 5659. 5. MEER~OTrER, V.: The ameloblastoma in the Witwatersrand area. 4th Proceedings International Academy Oral Pathology 1969, p. 144-156. 6. PINDBORG, J. J.: Pathology o] the dental hard tissues. 1st. Ed. Munksgaard, Copenhagen 2970, p. 371-375. 7. PINDBORG,J. J., KRAMER,2. R. H. & TORLONI, H.: Histological classification o/ odontogenie turnouts, jaw cysts and allied lesions. 1st Ed. WHO, Geneva 1971. 8. PRAETORIUS) F.: Calcifying odontogenic cyst: range variations and neoplastic potential. Int. J. Oral Surg. 2975: 4 : 8 9 (Abstr). 9. SHAFER, W. G., HINE, M. K. & LEVY, B. M.: A textbook o] oral pathology. 3rd Ed. W. B. Saunders Company, Philadelphia 1974. 10. SMALL, I. A. • WALDRON, C. A.: Ameloblastomas of the jaws. Oral Surg. 1965: 8: 281-297.
