378
A Case of Ameloblastoma Presenting an Exophytic Gingival Lesion*
as
Alastair R. L. Stevenson and Bruce W. Austin
Ameloblastomas are predominantly benign, intra-osseous odontogenic tumors and mucosal involvement is a rare secondary phenomenon, occurring only after a long period of intra-osseous growth and bone expansion. A case is reported of an intra-osseous multicystic (solid) ameloblastoma which presented as an exophytic gingival lesion in the left mandibular third molar region. A classification of exophytic gingival lesions is presented and the clinical features and management of ameloblastomas discussed. /
Periodontol 1990;60:378-381.
Key Words: Ameloblastoma; odontogenic tumor; gingiva, exophylic lesions.
Exophytic gingival lesions regularly present to the periodontist and a provisional diagnosis is often made on the nature of the clinical presentation. A useful classification, based on clinical appearance, has been developed by Poswillo et al.1 (Table 1). The soft, hemorrhagic pyogenic granuloma associated with chronic periodontal irritation and infection is the gingival lesion which presents most commonly, while a more florid example of the same lesion occurs during pregnancy as a result of hormonal changes. The firm, non-hemorrhagic gingival lesions are less common and often, being asymptomatic, are only identified at clinical examination. Such a lesion, which proved to have an unusual pathogenesis, is presented. CASE REPORT A 47-year-old Caucasian female was referred to the Department of Oral Surgery at the United Dental Hospital of Sydney by her periodontist for management of an exophytic lesion on the alveolar crest distal, and in close approximation to the left mandibular third molar (Figs. 1 and 2). The patient reported that the lesion had been present for approximately 1 month and was asymptomatic. It measured about 10 mm in diameter and extended about 5 mm above the alveolar crest. It was of firm consistency with no hemorrhagic tendency and had a leukoplakic, verrucous surface. The third molar was vital and asymptomatic. A periapical radiograph revealed an area of radiolucency 8 mm in diameter, demarcated by a radiopaque margin, extending from the distal root of the third molar in an arc to the alveolar crest posteriorly (Fig. 3). Review of a bitewing radiograph taken 4 years previously also showed some evidence of this radiolucent area (Fig. 4). There was no
'Department of Oral Surgery, Faculty of Dentistry, University of Sydney,
Australia.
Table 1.
Exophytic Gingival
Lesions
Firm, Non-Hemorrhagic
Soft, Hemorrhagic Pyogenic granuloma Pregnancy tumor Peripheral giant cell granuloma
Papilloma Fibro-epithelial polyp Peripheral fibroma
Brown tumor
Neurofibroma
Lipoma
Ameloblastoma Verrucous squamous cell carcinoma Granular cell myoblastoma Drug induced Phenytoin -
Cyclosporin
A classification of exophytic (after Poswillo et al.)'
gingival
lesions in the adult dentate
patient
relevant medical history and all routine hematological and biochemical tests were within normal limits. Under naso-endotracheal general anesthesia, the lesion and surrounding tissue were resected. The specimen consisted of a block of bone from above the mandibular canal incorporating the third molar and distal alveolar process in conjunction with a margin of normal buccal and lingual mucosa. During mobilization of the specimen a straw-colored fluid discharged from the alveolar component of the lesion. The lingual and inferior dental nerves were both identified intact and the defect was closed primarily with non-resorbable sutures. Postoperative recovery was uneventful and the patient reported no impairment of lingual or mental nerve function.
Histology
Histological
examination showed the follicular and cystic ameloblastoma in the deeper aspects of the tumor (Fig. 5) and an acanthomatous pattern superficially (Fig. 6). The tumor also merged with the mucosa over a wide area (Fig. 7) and had caused a deep depression in the underlying bone without evidence of invasion. There was
patterns of
an
Volume 61 Number 6
STEVENSON, AUSTIN
379
3. Periapical radiograph showing a well-defined unilocular, radiolucent lesion occupying the alveolar ridge distal to the mandibular third molar.
Figure
Figure I. Mirror photograph of the superior aspect of the exophytic lesion distal to the left mandibular third molar. Note leukaplakic verrucous surface.
Figure 4. A section of a bite-wing radiograph taken 4 years previously showing some evidence of radiolucency distal to the mandibular third molar.
19th
century.2 Three types can be recognized clinically and radiographically.3 Two are intra-osseous and the third is
Figure 2. no
Mirror photograph
of the lateral aspect of the exophytic lesion.
evidence of third molar root résorption. The findings consistent with a diagnosis of ameloblastoma.
were
DISCUSSION The ameloblastoma is a benign but locally destructive odontogenic tumor which accounts for about 1% of maxillary and mandibular bone tumors.2 It is almost exclusively found within the tooth-bearing portion of the jaws and has fascinated the profession since its first description in the mid-
confined to the soft tissues. The solid or multicystic ameloblastoma is the most commonly encountered type. It is slow growing, often manifesting clinically as an asymptomatic alveolar bone enlargement. Radiographically it has a multilocular cystic appearance often combined with root résorption of involved teeth. If not resected adequately it has a tendency to recur. The plexiform unicystic ameloblastoma (also referred to as mural), is less common and resembles a dentigerous cyst both clinically and radiographically. It has histological similarities to the multicystic type but less tendency to recur, even when surgery is restricted to enucleation.3 The peripheral (extra-osseous) ameloblastoma is the least
J Periodontol
380
AMELOBLASTOMA PRESENTING AS AN
EPULIS_June 1990
Figure 5. A photomicrograph of the deep aspect of the both follicular and cystic patterns (H & 40 orig.).
tumor
showing
Figure 7. A photomicrograph of the relationship of the overlying mucosa (H & E 40 orig.). Figure 6. A photomicrograph of the superficial aspect of the tumor showWO orig.). ing the acanthomatous pattern ( &
common osseous
type. Although histologically identical to the intra-
ameloblastomas,
it is confined to the soft tissues
overlying the tooth-bearing alveolar process.3 It presents clinically as an exophytic gingival lesion and rarely affects the underlying bone, although pressure résorption without infiltration has been to
prevent
reported.4 Local excision
is sufficient
recurrence.
in this case presented a dicould either be an intra-osseous lemma, in that the lesion ameloblastoma with a predominant mucosal component or a peripheral ameloblastoma causing bone résorption, both of which are rare manifestations. A detailed reappraisal of the clinical, radiographie, and histological material was needed before a definitive diagnosis of type was made. The initial exophytic presentation of the lesion was suggestive of a peripheral ameloblastoma; however, the short history, the presence of an underlying radiolucent lesion, and the absence of a soft tissue shadow on the original radiograph (Fig. 4) undermined the support for this diag-
The
histological diagnosis
tumour to
the
nosis (personal communications: Gardner DG, 1988; Radden BG, 1987). A unilocular radiolucency in the mandibular molar region could equally suggest a plexiform unicystic ameloblastoma; however, the age of the patient and histological configuration of the cystic areas failed to support this diagnosis (personal communicatiomGardner DG: 1988).3 The tumor was, therefore, finally categorized as an intraosseous multicystic ameloblastoma extending preferentially to a peripheral site and merging with the overlying epithelium, thus creating the exophytic lesion seen clinically. Ideally, if a lesion is suspected of being an ameloblastoma, the type should be established by clinical and biopsy examination in order that the appropriate surgical treatment can be instigated.3 However, this may not always be possible and in this case a pre-operative diagnosis was not established because the patient was reluctant to have a biopsy under local anesthetic. An excisional biopsy/marginal resection was, therefore, indicated because of the clinical features of the lesion and the patient's reluctance to undergo further surgery. Enucleation of the intra-osseous component of the lesion or superficial excision of the exophytic component would, in this case, have predisposed the patient to a recurrence. A marginal resection minimizes this possi-
Volume 61 Number 6
bility; however, in retrospect, it would also have been prudent to treat the resulting mandibular defect with either cryotherapy5 or a caustic agent such as Carnoy's solution6 to eradicate any possible cancellous bone infiltration. Irrespective of the treatment provided, all patients with a diagnosis of ameloblastoma should be reviewed annually to enable early identification of any recurrence. In this case no recurrence is evident 2 years following surgery and the patient is successfully wearing a partial denture.
STEVENSON,
381
pathogenesis of an ameloblastoma has been stressed so that the appropriate treatment can be provided. REFERENCES 1. Poswillo D, Babajews A, Bailey M, Foster M. Dental, Oral and Maxillofacial Surgery. London: W. Heinemann Medical Books; 1986; 168-172. 2. Lucas AB.
3. 4. 5.
CONCLUSION A case has been presented of an intra-osseous multicystic ameloblastoma with interesting clinical, radiographie, and histological findings. The presentation of the tumor as an exophytic gingival lesion could invite diagnostic confusion with the more common exophytic lesions and the rare peripheral ameloblastoma. The importance of determining the
AUSTIN
Pathology of Oral Tumours. 4th ed. Edinburgh: Churchill Livingstone; 1984: 31-60. Gardner DG. A pathologist's approach to the treatment of ameloblastoma. / Oral Maxillofac Surg 1984; 42:161-166. Gardner DG. Peripheral ameloblastoma. Cancer 1977; 39:1625-1633. Bradley PF. Cryosurgery of the Maxillofacial Region, Vol. II. Florida,
CRC Press; 1986: 55-91. Stoelinga PJW, Bronkhorst FB. The incidence, multiple presentation and recurrence of agressive cysts of the jaws. / Cranio Maxillo Fac Surg 1988; 16:184-195. Send reprint requests to: Dr. A.R.L. Stevenson, Department of Oral Surgery, United Dental Hospital, 2 Chalmers Street, Surry Hills, N.S.W. 2010, Australia. Accepted for publication: December 22, 1989 6.
A Case of Ameloblastoma Presenting an Exophytic Gingival Lesion*
as
Alastair R. L. Stevenson and Bruce W. Austin
Ameloblastomas are predominantly benign, intra-osseous odontogenic tumors and mucosal involvement is a rare secondary phenomenon, occurring only after a long period of intra-osseous growth and bone expansion. A case is reported of an intra-osseous multicystic (solid) ameloblastoma which presented as an exophytic gingival lesion in the left mandibular third molar region. A classification of exophytic gingival lesions is presented and the clinical features and management of ameloblastomas discussed. /
Periodontol 1990;60:378-381.
Key Words: Ameloblastoma; odontogenic tumor; gingiva, exophylic lesions.
Exophytic gingival lesions regularly present to the periodontist and a provisional diagnosis is often made on the nature of the clinical presentation. A useful classification, based on clinical appearance, has been developed by Poswillo et al.1 (Table 1). The soft, hemorrhagic pyogenic granuloma associated with chronic periodontal irritation and infection is the gingival lesion which presents most commonly, while a more florid example of the same lesion occurs during pregnancy as a result of hormonal changes. The firm, non-hemorrhagic gingival lesions are less common and often, being asymptomatic, are only identified at clinical examination. Such a lesion, which proved to have an unusual pathogenesis, is presented. CASE REPORT A 47-year-old Caucasian female was referred to the Department of Oral Surgery at the United Dental Hospital of Sydney by her periodontist for management of an exophytic lesion on the alveolar crest distal, and in close approximation to the left mandibular third molar (Figs. 1 and 2). The patient reported that the lesion had been present for approximately 1 month and was asymptomatic. It measured about 10 mm in diameter and extended about 5 mm above the alveolar crest. It was of firm consistency with no hemorrhagic tendency and had a leukoplakic, verrucous surface. The third molar was vital and asymptomatic. A periapical radiograph revealed an area of radiolucency 8 mm in diameter, demarcated by a radiopaque margin, extending from the distal root of the third molar in an arc to the alveolar crest posteriorly (Fig. 3). Review of a bitewing radiograph taken 4 years previously also showed some evidence of this radiolucent area (Fig. 4). There was no
'Department of Oral Surgery, Faculty of Dentistry, University of Sydney,
Australia.
Table 1.
Exophytic Gingival
Lesions
Firm, Non-Hemorrhagic
Soft, Hemorrhagic Pyogenic granuloma Pregnancy tumor Peripheral giant cell granuloma
Papilloma Fibro-epithelial polyp Peripheral fibroma
Brown tumor
Neurofibroma
Lipoma
Ameloblastoma Verrucous squamous cell carcinoma Granular cell myoblastoma Drug induced Phenytoin -
Cyclosporin
A classification of exophytic (after Poswillo et al.)'
gingival
lesions in the adult dentate
patient
relevant medical history and all routine hematological and biochemical tests were within normal limits. Under naso-endotracheal general anesthesia, the lesion and surrounding tissue were resected. The specimen consisted of a block of bone from above the mandibular canal incorporating the third molar and distal alveolar process in conjunction with a margin of normal buccal and lingual mucosa. During mobilization of the specimen a straw-colored fluid discharged from the alveolar component of the lesion. The lingual and inferior dental nerves were both identified intact and the defect was closed primarily with non-resorbable sutures. Postoperative recovery was uneventful and the patient reported no impairment of lingual or mental nerve function.
Histology
Histological
examination showed the follicular and cystic ameloblastoma in the deeper aspects of the tumor (Fig. 5) and an acanthomatous pattern superficially (Fig. 6). The tumor also merged with the mucosa over a wide area (Fig. 7) and had caused a deep depression in the underlying bone without evidence of invasion. There was
patterns of
an
Volume 61 Number 6
STEVENSON, AUSTIN
379
3. Periapical radiograph showing a well-defined unilocular, radiolucent lesion occupying the alveolar ridge distal to the mandibular third molar.
Figure
Figure I. Mirror photograph of the superior aspect of the exophytic lesion distal to the left mandibular third molar. Note leukaplakic verrucous surface.
Figure 4. A section of a bite-wing radiograph taken 4 years previously showing some evidence of radiolucency distal to the mandibular third molar.
19th
century.2 Three types can be recognized clinically and radiographically.3 Two are intra-osseous and the third is
Figure 2. no
Mirror photograph
of the lateral aspect of the exophytic lesion.
evidence of third molar root résorption. The findings consistent with a diagnosis of ameloblastoma.
were
DISCUSSION The ameloblastoma is a benign but locally destructive odontogenic tumor which accounts for about 1% of maxillary and mandibular bone tumors.2 It is almost exclusively found within the tooth-bearing portion of the jaws and has fascinated the profession since its first description in the mid-
confined to the soft tissues. The solid or multicystic ameloblastoma is the most commonly encountered type. It is slow growing, often manifesting clinically as an asymptomatic alveolar bone enlargement. Radiographically it has a multilocular cystic appearance often combined with root résorption of involved teeth. If not resected adequately it has a tendency to recur. The plexiform unicystic ameloblastoma (also referred to as mural), is less common and resembles a dentigerous cyst both clinically and radiographically. It has histological similarities to the multicystic type but less tendency to recur, even when surgery is restricted to enucleation.3 The peripheral (extra-osseous) ameloblastoma is the least
J Periodontol
380
AMELOBLASTOMA PRESENTING AS AN
EPULIS_June 1990
Figure 5. A photomicrograph of the deep aspect of the both follicular and cystic patterns (H & 40 orig.).
tumor
showing
Figure 7. A photomicrograph of the relationship of the overlying mucosa (H & E 40 orig.). Figure 6. A photomicrograph of the superficial aspect of the tumor showWO orig.). ing the acanthomatous pattern ( &
common osseous
type. Although histologically identical to the intra-
ameloblastomas,
it is confined to the soft tissues
overlying the tooth-bearing alveolar process.3 It presents clinically as an exophytic gingival lesion and rarely affects the underlying bone, although pressure résorption without infiltration has been to
prevent
reported.4 Local excision
is sufficient
recurrence.
in this case presented a dicould either be an intra-osseous lemma, in that the lesion ameloblastoma with a predominant mucosal component or a peripheral ameloblastoma causing bone résorption, both of which are rare manifestations. A detailed reappraisal of the clinical, radiographie, and histological material was needed before a definitive diagnosis of type was made. The initial exophytic presentation of the lesion was suggestive of a peripheral ameloblastoma; however, the short history, the presence of an underlying radiolucent lesion, and the absence of a soft tissue shadow on the original radiograph (Fig. 4) undermined the support for this diag-
The
histological diagnosis
tumour to
the
nosis (personal communications: Gardner DG, 1988; Radden BG, 1987). A unilocular radiolucency in the mandibular molar region could equally suggest a plexiform unicystic ameloblastoma; however, the age of the patient and histological configuration of the cystic areas failed to support this diagnosis (personal communicatiomGardner DG: 1988).3 The tumor was, therefore, finally categorized as an intraosseous multicystic ameloblastoma extending preferentially to a peripheral site and merging with the overlying epithelium, thus creating the exophytic lesion seen clinically. Ideally, if a lesion is suspected of being an ameloblastoma, the type should be established by clinical and biopsy examination in order that the appropriate surgical treatment can be instigated.3 However, this may not always be possible and in this case a pre-operative diagnosis was not established because the patient was reluctant to have a biopsy under local anesthetic. An excisional biopsy/marginal resection was, therefore, indicated because of the clinical features of the lesion and the patient's reluctance to undergo further surgery. Enucleation of the intra-osseous component of the lesion or superficial excision of the exophytic component would, in this case, have predisposed the patient to a recurrence. A marginal resection minimizes this possi-
Volume 61 Number 6
bility; however, in retrospect, it would also have been prudent to treat the resulting mandibular defect with either cryotherapy5 or a caustic agent such as Carnoy's solution6 to eradicate any possible cancellous bone infiltration. Irrespective of the treatment provided, all patients with a diagnosis of ameloblastoma should be reviewed annually to enable early identification of any recurrence. In this case no recurrence is evident 2 years following surgery and the patient is successfully wearing a partial denture.
STEVENSON,
381
pathogenesis of an ameloblastoma has been stressed so that the appropriate treatment can be provided. REFERENCES 1. Poswillo D, Babajews A, Bailey M, Foster M. Dental, Oral and Maxillofacial Surgery. London: W. Heinemann Medical Books; 1986; 168-172. 2. Lucas AB.
3. 4. 5.
CONCLUSION A case has been presented of an intra-osseous multicystic ameloblastoma with interesting clinical, radiographie, and histological findings. The presentation of the tumor as an exophytic gingival lesion could invite diagnostic confusion with the more common exophytic lesions and the rare peripheral ameloblastoma. The importance of determining the
AUSTIN
Pathology of Oral Tumours. 4th ed. Edinburgh: Churchill Livingstone; 1984: 31-60. Gardner DG. A pathologist's approach to the treatment of ameloblastoma. / Oral Maxillofac Surg 1984; 42:161-166. Gardner DG. Peripheral ameloblastoma. Cancer 1977; 39:1625-1633. Bradley PF. Cryosurgery of the Maxillofacial Region, Vol. II. Florida,
CRC Press; 1986: 55-91. Stoelinga PJW, Bronkhorst FB. The incidence, multiple presentation and recurrence of agressive cysts of the jaws. / Cranio Maxillo Fac Surg 1988; 16:184-195. Send reprint requests to: Dr. A.R.L. Stevenson, Department of Oral Surgery, United Dental Hospital, 2 Chalmers Street, Surry Hills, N.S.W. 2010, Australia. Accepted for publication: December 22, 1989 6.
