649
Peripheral Ameloblastoma of the Gingiva. A Case Report Sheldon Mintz,
*
Yakir Anavi,f William R. Sabes*
of gingival peripheral ameloblastoma are extremely rare and have been sporadic. This paper reports a pertinent case of a 40-year-old woman who for 2 years had a progressively enlarging asymptomatic firm mass in the buccal gingival region of the lower premolars. Cupping of the underlying bone was radiographically demonstrated. The lesion was excised surgically together with extraction of the first premolar, and no evidence of recurrence was seen 5 years later. The clinical, radiological, and histopathological characteristics of gingival peripheral ameloblastoma were analyzed in the 33 previously reported cases. The differential diagnosis and treatment of this case report are
Reports
discussed. / Periodontol
1990; 61:649-652.
Key Words: Gingival neoplasm; ameloblastoma, gingival peripheral; bone neoplasms.
Ameloblastoma most commonly originates centrally within the jaws, but it may also arise in a peripheral extraosseous location.1 Gingival peripheral ameloblastoma is an ex-
tremely rare, benign, encapsulated, exophytic, odontogenic tumor arising in the tooth-bearing gingiva or other oral soft tissues. It exhibits the same histologie features of a typical
intraosseous ameloblastoma, but it is different in its biologic behavior. While the intraosseous ameloblastoma is locally aggressive with invasion and destruction of bone, the peripheral ameloblastoma generally lacks this persistent invasiveness. The following case describes peripheral ameloblastoma of the gingiva, and presents the opportunity for analyzing the clinical and histological aspects of previously
reported
cases.
CASE REPORT A 40-year-old woman
presented
with a painless mass enthe larging progressively past 2 years in the buccal of the left lower first and second premolars. gingival region The past medical history disclosed surgery for meningioma of the right mastoid process 20 years earlier, which resulted in a right facial palsy. The gingival mass (Fig. 1) was well demarcated measuring 2.5 x 1.5 1.5 cm, sessile, firm, a A torus mandibularis with normal mucosal color. smooth, was located on the lingual alveolus of the left premolars and the first molar. Further head and neck examination was unremarkable. Radiographie studies revealed an osteosover
*
Department of Oral Pathology, University of Detroit, School tistry, Detroit, MI. Department of Oral and Maxillofacial Surgery, Sackler Faculty icine, Tel Aviv University, Israel.
of Denof Med-
Figure 1. Peripheral ameloblastoma of the buccal gingiva, and mandibular leftfirst and second premolars. Note the torus mandibularis opposite the
tumor mass.
650
J Periodontol October 1990
PERIPHERAL AMELOBLASTOMA OF THE GINGIVA
3. Photomicrograph showing the peripheral pallisading layer of islands. Also, note stellate reticulum-like areas and squamous metaplasia centrally within islands of tumor (H & E; original magnification
Figure tumor x
66).
which displayed regular rete peg formation. It was well demarcated from the underlying fibrous connective tissue which contained numerous islands and strands of tumor. The tumor islands had a peripheral layer of pallisading columnar cells. Towards the center small amounts of stellate reticulum-like epithelial cells were present. Squamoid tranformation with epithelial pearl-like structures were seen in many of the islands of tumor (Fig. 3). In some areas the stroma consisted of fairly delicate collagen fibers and other areas were more highly collagenized. The histologie findings were consistent with a diagnosis of peripheral ameloblastoma, acanthomatous type.
epithelium
Figure 2. Occluseti film showing the cortical periosteal "cupping" beneath the tumor (arrow), and the torus mandibularis on the lingual aspect. clerotic density of the premolars and first molar areas, which consistent anatomically for the lingual torus. There was no evidence of intrabody destruction nor loculation. The occlusal film showed cortical periosteal cupping beneath the gingival lesion (Fig. 2). The differential diagnosis included: peripheral odontogenic fibroma, peripheral ossifying fibroma, irritative fibroma, pyogenic granuloma, peripheral giant cell granuloma, and peripheral ameloblastoma. A wide excision of the mass was performed. The surgical procedure consisted of a full thickness gingival resection from the first premolar to the first molar area. The first premolar tooth was extracted and the surrounding circumferential gingival tissue was also resected. Clinical inspection of the extraction socket, infrabony area, and lingual and buccal cortical plates revealed no tumor involvement. The resected surgical area was packed open with iodoform gauze, sutured to the peripheral soft tissue margins, and fixed by interdental sutures. The surgical wound healed uneventfully. The patient has now been followed for 5 years, without any signs of recurrence. was
Pathological Findings
surgical soft tissue specimen was pale-brown, ovoid in shape, measuring 2.5 x 1.5 x 1.5 cm. On cut section, the specimen was covered by an orderly stratified squamous
The
REVIEW OF THE LITERATURE Reports of peripheral ameloblastoma of the gingiva are very scarce. Review of the international literature revealed only 33 cases, from 1959 through 1989.2-32 The clinical and histopathological features, including the present case, were
analyzed.
Age and Sex Age of the patients
at the time of presentation ranged from 16 to 92 years, with a mean age of 48.6 years and maximum frequency in the 4th and 5th decades. One of the 33 reviewed cases occurred in adolescence32 and none in childhood. There is a male predominance (M/F= 1.7:1). Racial predilection could not be determined due to lack of detailed information in some of the reports.
Location There is a 2:1 predilection for the dentulous regions to be affected in comparison to edentulous areas. The mandible is the more common site (74%), and to the premolar, lingual gingival region the most affected (64%). In the maxilla, the most common location was the edentulous tuberosity
region (63%).
Volume 61 Number 10
MINTZ, ANAVI, SABES
Clinical Description In all the reviewed cases, the main clinical presentation was a painless progressively enlarging mass. The appearance of the tumor varied considerably. The various clinical descriptions had no significant predilection for specific location and may be subdivided as follows: 1. Base: Most of the lesions have sessile, broad or pedunculated base. 2. Consistency: Most commonly it is firm. 3. Surface: Usually it is smooth, but many other descriptions have been reported. 4. Color: Most commonly described as normal pink.
Size The tumors ranged between 0.2 and 4.0 with a mean of 1.4 cm.
cm
in diameter,
Symptoms Early symptoms were absent or minimal and these tumors are usually asymptomatic. In 19 of 34 patients the time since the patient first noticed the lesion ranged from 1 month
to 5 years, with an average of 1 year.
Bone Status In 24 out of 34 reported nor surgical evidence of
Underlying
there was no radiological involvement. Three cases exhibited a bony erosion, two had superficial invasion and one an interdental alveolar bone résorption. Only in the present case was cupping of underlying bone described. cases
bony
Histopathology
In 31 of the 34 cases, a subclassification as to the histologie type of peripheral ameloblastoma was reported. The acanthomatous type was the most prevalent, being present in 43.3%. Next were the plexiform (23.3%) and the follicular (16.7%) types. Another 16.7% of the cases were reported as combinations of reticular, basaloid, and/or acanthomatous types. All three cases 3'5'18 in which local recurrence was reported were of the acanthomatous type. In another case,30 metastasis to cervical lymph nodes was reported to have occurred 2 days post surgery of a follicular peripheral ameloblastoma. The histology of the metastatic site was reported to be compatible with ameloblastic carcinoma. Its rarity precludes prospective trials to draw conclusions as to which type of peripheral ameloblastoma, if any, may be more likely to recur. Moreover, it may generally be concluded from the reviewed cases that no correlation exists between histologie pattern type and clinical behavior.
Treatment In all the reviewed cases, treatment was always surgical, varying from a simple excision to a more radical procedure such as alveolar segmental resection. Other treatment protocols included excision with curettage of the underlying bone and excision with tooth extraction.
Follow
651
Up
Follow-up
information was available on 25 patients. No evidence of disease was recorded in 21 patients, ranging from 6 months to 8 years with a mean time of 37 months post surgery. Three recurrent cases (9%) were found 2 months,3 17 months,5 and 5 years18 after initial surgery. One patient30 developed supraclavicualr lymph node metastasis and died 7 days post surgery of pleural effusion. DISCUSSION Peripheral ameloblastoma appears mostly in the gingiva. There are only a few reports on other intraoral peripheral ameloblastomas located in the cheek33-35 or floor of the mouth.36 The etiopathogenesis of peripheral ameloblastoma is controversial and not definitely established. The possible origin is either from epithelial remnants of the dental lamina and its enamel organ derivatives within the underlying connective tissue, or from the basal cell layer of the oral mu-
cosa_3,5,9,12,38
Clinically the gingival tumor in this case appeared as an asymptomatic, firm, slowly enlarging mass, with a smooth, normally looking mucosa. The following entities were included in the preoperative differential diagnosis: gingival tumors, such as peripheral ossifying fibroma, peripheral odontogenic fibroma, or inflammatory hyperplastic lesions such as pyogenic granuloma or peripheral giant cell granuloma. According to the reports in the literature, the clinical descriptions of peripheral ameloblastoma varied considerably. The peripheral ossifying and odontogenic fibromas usually also show various clinical appearances37 and may closely resemble peripheral ameloblastoma. Therefore, clinical appearance of these tumors is not pathognomonic and the diagnosis can only be identified by histologie examination. However, the peripheral fibromas frequently cause a separation of the adjacent teeth, and occasionally minimal bone résorption. Furthermore, if the calcified element is significant, radiopaque foci will be observed within the soft
tissue tumor mass on radiographs.37 The second group of conditions that should be considered in the differential diagnosis are the inflammatory gingival hyperplasias. These conditions have a possible identical basic pathogenesis which is chronic trauma. Therefore, elimination of the chronic causative irritants, such as calculus or overhanging margins of dental restorations, will usually result in its regression. Clinically the pyogenic granuloma is an asymptomatic mass usually with a rough, ulcerated necrotic surface. In the granulomatous stage it will appear red, soft, and bleed readily. Peripheral giant cell granuloma appears red, pink, or bluish in color. It is most often nodular or polypoid in shape, and may be soft to hard.37 The case reported here failed to invade bone. Only six of the previously reported cases reported a minimal bony erosion, invasion, and résorption underneath the lesions, and there is generally no evidence of severe bony destruction. This finding is in distinct contrast to the osteolytic nature of the intraosseous ameloblastoma. Of interest in this case was the presence of
652
cupping in the bone underlying the lesion. This can be explained as a mechanical process resulting from periosteal response to the tumoral pressure. Except for Gardner's review of the peripheral ameloblastoma,38 this case is the only report in which bone cupping is demonstrated. Peripheral ameloblastoma is characterized as a tumor with no tendency to recur. Except for only three recurrent cases, none of these cases manifested the aggressive or invasive behavior of the central ameloblastoma. Most probably, the incomplete removal of the tumor was responsible for its recurrence
in the three aforementioned
metastasize, and only in
cases.
case30
It is not prone
malignant potential with metastasis demonstrated. This non-aggressive biological behavior of the peripheral ameloblastoma may formulate a coherent treatment policy. Local excision with adequate margin of normal tissue, and with curettage to
one
was a
teeth extractions if needed, is the treatment of choice. A radical procedure of bony resection appears unjustified as peripheral ameloblastoma is not an aggressive tumor and invades bone very rarely. Thusfar, these straightforward results may draw conclusions on the surgical treatment performed in this case. Extraction of the first premolar together with excision of the tumor was accomplished, because the tumor proliferated significantly into the interdental papilla. In our judgement it was important to remove the tumor completely at the first attempt. However, on second thought, we tend to believe that a conservative surgery treatment with adequate margins and without extraction of the tooth would be more or
appropriate. REFERENCES 1. Pindborg JJ, Kramer IR. Histological Typing of Odontogenic Tumors, Jaw Cysts and Allied Lesion. Geneva: World Health Organization; 1971:30-31.
2.
3.
Stanley HR, Krogh HW. Peripheral ameloblastoma: Report of a case. Oral Surg Oral Med Oral Pathol 1959; 12:760-765. Russell A. Ameloblastoma of mucosal origin. NZ Dent J 1966; 62:116—
118. 4. Lee KW, Chin
TC, Paul G. Peripheral ameloblastoma.
Br J Oral 8:150-153. Wertheimer FW, Stroud DE. Peripheral ameloblastoma in a papilloma with recurrence: Report of a case. J Oral Surg Oral Med Oral Pathol 1972; 30:47-49. Wallen NG. Extraosseous ameloblastoma. Oral Surg Oral Med Oral Pathol 1972; 34:95-97. Balfour RS, Loscalzo LJ, Sulka M. Multicentric peripheral ameloblastoma. / Oral Surg 1973; 31:535-538. Simpson HE. Basal-cell carcinoma and peripheral ameloblastoma. Oral Surg Oral Med Oral Pathol 1974; 38:233-240. Richardson JR, Greer RO. Ameloblastoma of mucosal origin: A pathobiologic réévaluation. Arch Otolaryngol 1974; 100:174-175. Pansino FA, Meara JW. Case report: Peripheral ameloblastoma. / Mich DentAssoc 1975; 57:129-130. Frankel KA, Smith JD, Frankel LS. Soft tissure ameloblastoma in a 92-year-old woman. Arch Otolaryngol 1977: 103:499-500. Wesley RK, Borninski ER, Mintz S. Peripheral ameloblastoma: Re-
Maxillofac Surg 1970;
5.
6. 7.
8. 9. 10. 11.
12.
J Periodontol October 1990
PERIPHERAL AMELOBLASTOMA OF THE GINGIVA
port of case
and review of the literature. / Oral
Surg 1977;
35:670-
672. 13. Greer
RO, Hammond WS. Extraosseous ameloblastoma: Light microscopic and ultrastructural observations. / Oral Surg 1978; 36:553-
556. 14. Birkiholz H, Sills AH, Reíd RA. Peripheral ameloblastoma. J Am Dent Assoc 1978; 97:658-660. 15. Tongdee C, Ganggavakin S. Peripheral ameloblastoma (report of a case and review literature). / Dent Assn Thai 1978; 28:31-38. 16. Gould AR, Farman AG, DeJean , Van Arsdall LR. Peripheral ameloblastoma: An ultrastructural analysis. / Oral Path 1982; 11:90— 101. 17. Moskow BS, Baden E. The peripheral ameloblastoma of the gingiva: Case report and literature review. J Periodontol 1982; 53:736-742. 18. Guralnick W, Chuong R, Goodman M. Peripheral ameloblastoma of the gingiva. J Oral Maxillofac Surg 1983; 41:536-539. 19. Ide F, Saito I, Umenura S. Peripheral ameloblastoma: A case report. J Periodontol 1983; 54:173-174. 20. Patrikiou A, Papanicolaou S, Stylogianni E, Sotiriadou S. Peripheral ameloblastoma: Case report and review of the literature. Int J Oral Surg 1983; 12:51-55. 21. Schaberg SJ, Antimarino RF, Pierce GL, Crawford BE. Peripheral ameloblastoma: Report of a case. Int J Oral Surg 1983; 12:344-347. 22. Shiba R, Sakoda S, Yamada N. Peripheral ameloblastoma. J Oral Maxillofac Surg 1983; 41:460-463. 23. Urmacher C, Pearlman S. An uncommon neoplasm of the oral mucosa. Am J Dermatopathol 1983; 5:601-604. 24. Connolly SF, Sonis S, Lockhard PB. An unusually located early peripheral ameloblastoma. J Oral Med 1984; 39:180-182. 25. Anneroth G, Johansson B. Peripheral ameloblastoma. IntJ Oral Surg 1985; 14:295-299. 26. Kaneko Y, Ueno S. Peripheral ameloblastoma resembling a papilloma: Report of a case. J Oral Maxillofac Surg 1986; 44:737-739. 27. Ueno S, Nakamura S, Mushimoto , Shirasu R. A clinicopathologic study of ameloblastoma. / Oral Maxillofac Surg 1986; 44:361-365. 28. Ficarra G, Hansen LS. Peripheral ameloblastoma: A case report. / Craniomaxillofac Surg 1987; 15:110-112. 29. Horwitz I, Hirschberg A, Dayan D. Peripheral ameloblastoma: A clinical dilemma in gingival lesions. / Clin Periodontol 1987; 14:366369. 30. Lin SC, Lieu CM, Hahn LJ, Kwan HW. Peripheral ameloblastoma with metastasis. Int J Oral Maxillofac Surg 1987; 16:202-204. 31. Zen EC, Chen L. Peripheral ameloblastoma: A case report and review of literature. Chang Gung Med J 1987; 8:181-183. 32. Kahan MA. Ameloblastoma in young persons: A clinicopathologic analysis and etiologic investigation. Oral Surg 1989; 67:706-715. 33. Braunstein E. Case Report of an extraosseous adamantinoblastoma. Oral Surg Oral Med Oral Pathol 1949; 2:726-728. 34. Klinar KL, McManis JC. Soft-tissue ameloblastoma: Report of a case. Oral Surg Oral Med Oral Pathol 1969; 28:266-272. 35. Woo SB, Smith-Williams JE, Sciubba JJ, Lipper S. Peripheral ameloblastoma of the buccal mucosa: Case report and review of the English literature. Oral Surg Oral Med Oral Pathol 1987; 63:78-84. 36. Ramnarayan K., Nayak RG, Kávaiam A. Peripheral ameloblastoma. M J Oral Surg 1985; 14:300-301. 37. Wood NK, Goaz P. Differential Diagnosis of Oral Lesions. 3rd ed. St. Louis: The C.V. Mosby Company; 1985:148-158. 38. Gardner DG. Peripheral ameloblastoma: A study of 21 cases, including 5 reported as basal cell carcinoma of the gingiva. Cancer 1977; 39:1625-1633.
Send reprint requests to: Dr. Sheldon Mintz, 19855 Outer rison Place East, Dearborn, MI 48124. Accepted for publication April 19, 1990.
Drive, Gar-
Peripheral Ameloblastoma of the Gingiva. A Case Report Sheldon Mintz,
*
Yakir Anavi,f William R. Sabes*
of gingival peripheral ameloblastoma are extremely rare and have been sporadic. This paper reports a pertinent case of a 40-year-old woman who for 2 years had a progressively enlarging asymptomatic firm mass in the buccal gingival region of the lower premolars. Cupping of the underlying bone was radiographically demonstrated. The lesion was excised surgically together with extraction of the first premolar, and no evidence of recurrence was seen 5 years later. The clinical, radiological, and histopathological characteristics of gingival peripheral ameloblastoma were analyzed in the 33 previously reported cases. The differential diagnosis and treatment of this case report are
Reports
discussed. / Periodontol
1990; 61:649-652.
Key Words: Gingival neoplasm; ameloblastoma, gingival peripheral; bone neoplasms.
Ameloblastoma most commonly originates centrally within the jaws, but it may also arise in a peripheral extraosseous location.1 Gingival peripheral ameloblastoma is an ex-
tremely rare, benign, encapsulated, exophytic, odontogenic tumor arising in the tooth-bearing gingiva or other oral soft tissues. It exhibits the same histologie features of a typical
intraosseous ameloblastoma, but it is different in its biologic behavior. While the intraosseous ameloblastoma is locally aggressive with invasion and destruction of bone, the peripheral ameloblastoma generally lacks this persistent invasiveness. The following case describes peripheral ameloblastoma of the gingiva, and presents the opportunity for analyzing the clinical and histological aspects of previously
reported
cases.
CASE REPORT A 40-year-old woman
presented
with a painless mass enthe larging progressively past 2 years in the buccal of the left lower first and second premolars. gingival region The past medical history disclosed surgery for meningioma of the right mastoid process 20 years earlier, which resulted in a right facial palsy. The gingival mass (Fig. 1) was well demarcated measuring 2.5 x 1.5 1.5 cm, sessile, firm, a A torus mandibularis with normal mucosal color. smooth, was located on the lingual alveolus of the left premolars and the first molar. Further head and neck examination was unremarkable. Radiographie studies revealed an osteosover
*
Department of Oral Pathology, University of Detroit, School tistry, Detroit, MI. Department of Oral and Maxillofacial Surgery, Sackler Faculty icine, Tel Aviv University, Israel.
of Denof Med-
Figure 1. Peripheral ameloblastoma of the buccal gingiva, and mandibular leftfirst and second premolars. Note the torus mandibularis opposite the
tumor mass.
650
J Periodontol October 1990
PERIPHERAL AMELOBLASTOMA OF THE GINGIVA
3. Photomicrograph showing the peripheral pallisading layer of islands. Also, note stellate reticulum-like areas and squamous metaplasia centrally within islands of tumor (H & E; original magnification
Figure tumor x
66).
which displayed regular rete peg formation. It was well demarcated from the underlying fibrous connective tissue which contained numerous islands and strands of tumor. The tumor islands had a peripheral layer of pallisading columnar cells. Towards the center small amounts of stellate reticulum-like epithelial cells were present. Squamoid tranformation with epithelial pearl-like structures were seen in many of the islands of tumor (Fig. 3). In some areas the stroma consisted of fairly delicate collagen fibers and other areas were more highly collagenized. The histologie findings were consistent with a diagnosis of peripheral ameloblastoma, acanthomatous type.
epithelium
Figure 2. Occluseti film showing the cortical periosteal "cupping" beneath the tumor (arrow), and the torus mandibularis on the lingual aspect. clerotic density of the premolars and first molar areas, which consistent anatomically for the lingual torus. There was no evidence of intrabody destruction nor loculation. The occlusal film showed cortical periosteal cupping beneath the gingival lesion (Fig. 2). The differential diagnosis included: peripheral odontogenic fibroma, peripheral ossifying fibroma, irritative fibroma, pyogenic granuloma, peripheral giant cell granuloma, and peripheral ameloblastoma. A wide excision of the mass was performed. The surgical procedure consisted of a full thickness gingival resection from the first premolar to the first molar area. The first premolar tooth was extracted and the surrounding circumferential gingival tissue was also resected. Clinical inspection of the extraction socket, infrabony area, and lingual and buccal cortical plates revealed no tumor involvement. The resected surgical area was packed open with iodoform gauze, sutured to the peripheral soft tissue margins, and fixed by interdental sutures. The surgical wound healed uneventfully. The patient has now been followed for 5 years, without any signs of recurrence. was
Pathological Findings
surgical soft tissue specimen was pale-brown, ovoid in shape, measuring 2.5 x 1.5 x 1.5 cm. On cut section, the specimen was covered by an orderly stratified squamous
The
REVIEW OF THE LITERATURE Reports of peripheral ameloblastoma of the gingiva are very scarce. Review of the international literature revealed only 33 cases, from 1959 through 1989.2-32 The clinical and histopathological features, including the present case, were
analyzed.
Age and Sex Age of the patients
at the time of presentation ranged from 16 to 92 years, with a mean age of 48.6 years and maximum frequency in the 4th and 5th decades. One of the 33 reviewed cases occurred in adolescence32 and none in childhood. There is a male predominance (M/F= 1.7:1). Racial predilection could not be determined due to lack of detailed information in some of the reports.
Location There is a 2:1 predilection for the dentulous regions to be affected in comparison to edentulous areas. The mandible is the more common site (74%), and to the premolar, lingual gingival region the most affected (64%). In the maxilla, the most common location was the edentulous tuberosity
region (63%).
Volume 61 Number 10
MINTZ, ANAVI, SABES
Clinical Description In all the reviewed cases, the main clinical presentation was a painless progressively enlarging mass. The appearance of the tumor varied considerably. The various clinical descriptions had no significant predilection for specific location and may be subdivided as follows: 1. Base: Most of the lesions have sessile, broad or pedunculated base. 2. Consistency: Most commonly it is firm. 3. Surface: Usually it is smooth, but many other descriptions have been reported. 4. Color: Most commonly described as normal pink.
Size The tumors ranged between 0.2 and 4.0 with a mean of 1.4 cm.
cm
in diameter,
Symptoms Early symptoms were absent or minimal and these tumors are usually asymptomatic. In 19 of 34 patients the time since the patient first noticed the lesion ranged from 1 month
to 5 years, with an average of 1 year.
Bone Status In 24 out of 34 reported nor surgical evidence of
Underlying
there was no radiological involvement. Three cases exhibited a bony erosion, two had superficial invasion and one an interdental alveolar bone résorption. Only in the present case was cupping of underlying bone described. cases
bony
Histopathology
In 31 of the 34 cases, a subclassification as to the histologie type of peripheral ameloblastoma was reported. The acanthomatous type was the most prevalent, being present in 43.3%. Next were the plexiform (23.3%) and the follicular (16.7%) types. Another 16.7% of the cases were reported as combinations of reticular, basaloid, and/or acanthomatous types. All three cases 3'5'18 in which local recurrence was reported were of the acanthomatous type. In another case,30 metastasis to cervical lymph nodes was reported to have occurred 2 days post surgery of a follicular peripheral ameloblastoma. The histology of the metastatic site was reported to be compatible with ameloblastic carcinoma. Its rarity precludes prospective trials to draw conclusions as to which type of peripheral ameloblastoma, if any, may be more likely to recur. Moreover, it may generally be concluded from the reviewed cases that no correlation exists between histologie pattern type and clinical behavior.
Treatment In all the reviewed cases, treatment was always surgical, varying from a simple excision to a more radical procedure such as alveolar segmental resection. Other treatment protocols included excision with curettage of the underlying bone and excision with tooth extraction.
Follow
651
Up
Follow-up
information was available on 25 patients. No evidence of disease was recorded in 21 patients, ranging from 6 months to 8 years with a mean time of 37 months post surgery. Three recurrent cases (9%) were found 2 months,3 17 months,5 and 5 years18 after initial surgery. One patient30 developed supraclavicualr lymph node metastasis and died 7 days post surgery of pleural effusion. DISCUSSION Peripheral ameloblastoma appears mostly in the gingiva. There are only a few reports on other intraoral peripheral ameloblastomas located in the cheek33-35 or floor of the mouth.36 The etiopathogenesis of peripheral ameloblastoma is controversial and not definitely established. The possible origin is either from epithelial remnants of the dental lamina and its enamel organ derivatives within the underlying connective tissue, or from the basal cell layer of the oral mu-
cosa_3,5,9,12,38
Clinically the gingival tumor in this case appeared as an asymptomatic, firm, slowly enlarging mass, with a smooth, normally looking mucosa. The following entities were included in the preoperative differential diagnosis: gingival tumors, such as peripheral ossifying fibroma, peripheral odontogenic fibroma, or inflammatory hyperplastic lesions such as pyogenic granuloma or peripheral giant cell granuloma. According to the reports in the literature, the clinical descriptions of peripheral ameloblastoma varied considerably. The peripheral ossifying and odontogenic fibromas usually also show various clinical appearances37 and may closely resemble peripheral ameloblastoma. Therefore, clinical appearance of these tumors is not pathognomonic and the diagnosis can only be identified by histologie examination. However, the peripheral fibromas frequently cause a separation of the adjacent teeth, and occasionally minimal bone résorption. Furthermore, if the calcified element is significant, radiopaque foci will be observed within the soft
tissue tumor mass on radiographs.37 The second group of conditions that should be considered in the differential diagnosis are the inflammatory gingival hyperplasias. These conditions have a possible identical basic pathogenesis which is chronic trauma. Therefore, elimination of the chronic causative irritants, such as calculus or overhanging margins of dental restorations, will usually result in its regression. Clinically the pyogenic granuloma is an asymptomatic mass usually with a rough, ulcerated necrotic surface. In the granulomatous stage it will appear red, soft, and bleed readily. Peripheral giant cell granuloma appears red, pink, or bluish in color. It is most often nodular or polypoid in shape, and may be soft to hard.37 The case reported here failed to invade bone. Only six of the previously reported cases reported a minimal bony erosion, invasion, and résorption underneath the lesions, and there is generally no evidence of severe bony destruction. This finding is in distinct contrast to the osteolytic nature of the intraosseous ameloblastoma. Of interest in this case was the presence of
652
cupping in the bone underlying the lesion. This can be explained as a mechanical process resulting from periosteal response to the tumoral pressure. Except for Gardner's review of the peripheral ameloblastoma,38 this case is the only report in which bone cupping is demonstrated. Peripheral ameloblastoma is characterized as a tumor with no tendency to recur. Except for only three recurrent cases, none of these cases manifested the aggressive or invasive behavior of the central ameloblastoma. Most probably, the incomplete removal of the tumor was responsible for its recurrence
in the three aforementioned
metastasize, and only in
cases.
case30
It is not prone
malignant potential with metastasis demonstrated. This non-aggressive biological behavior of the peripheral ameloblastoma may formulate a coherent treatment policy. Local excision with adequate margin of normal tissue, and with curettage to
one
was a
teeth extractions if needed, is the treatment of choice. A radical procedure of bony resection appears unjustified as peripheral ameloblastoma is not an aggressive tumor and invades bone very rarely. Thusfar, these straightforward results may draw conclusions on the surgical treatment performed in this case. Extraction of the first premolar together with excision of the tumor was accomplished, because the tumor proliferated significantly into the interdental papilla. In our judgement it was important to remove the tumor completely at the first attempt. However, on second thought, we tend to believe that a conservative surgery treatment with adequate margins and without extraction of the tooth would be more or
appropriate. REFERENCES 1. Pindborg JJ, Kramer IR. Histological Typing of Odontogenic Tumors, Jaw Cysts and Allied Lesion. Geneva: World Health Organization; 1971:30-31.
2.
3.
Stanley HR, Krogh HW. Peripheral ameloblastoma: Report of a case. Oral Surg Oral Med Oral Pathol 1959; 12:760-765. Russell A. Ameloblastoma of mucosal origin. NZ Dent J 1966; 62:116—
118. 4. Lee KW, Chin
TC, Paul G. Peripheral ameloblastoma.
Br J Oral 8:150-153. Wertheimer FW, Stroud DE. Peripheral ameloblastoma in a papilloma with recurrence: Report of a case. J Oral Surg Oral Med Oral Pathol 1972; 30:47-49. Wallen NG. Extraosseous ameloblastoma. Oral Surg Oral Med Oral Pathol 1972; 34:95-97. Balfour RS, Loscalzo LJ, Sulka M. Multicentric peripheral ameloblastoma. / Oral Surg 1973; 31:535-538. Simpson HE. Basal-cell carcinoma and peripheral ameloblastoma. Oral Surg Oral Med Oral Pathol 1974; 38:233-240. Richardson JR, Greer RO. Ameloblastoma of mucosal origin: A pathobiologic réévaluation. Arch Otolaryngol 1974; 100:174-175. Pansino FA, Meara JW. Case report: Peripheral ameloblastoma. / Mich DentAssoc 1975; 57:129-130. Frankel KA, Smith JD, Frankel LS. Soft tissure ameloblastoma in a 92-year-old woman. Arch Otolaryngol 1977: 103:499-500. Wesley RK, Borninski ER, Mintz S. Peripheral ameloblastoma: Re-
Maxillofac Surg 1970;
5.
6. 7.
8. 9. 10. 11.
12.
J Periodontol October 1990
PERIPHERAL AMELOBLASTOMA OF THE GINGIVA
port of case
and review of the literature. / Oral
Surg 1977;
35:670-
672. 13. Greer
RO, Hammond WS. Extraosseous ameloblastoma: Light microscopic and ultrastructural observations. / Oral Surg 1978; 36:553-
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Send reprint requests to: Dr. Sheldon Mintz, 19855 Outer rison Place East, Dearborn, MI 48124. Accepted for publication April 19, 1990.
Drive, Gar-
