Peripheral Ameloblastoma: an Etiology from Surface Epithelium? Case Report and Review of Literature

Oral Oncology EXTRA (2005) 41, 211–215

http://intl.elsevierhealth.com/journal/ooex

CASE REPORT Peripheral ameloblastoma: An etiology from surface epithelium? Case report and review of literature

Kishore Shetty *

LSU Health Sciences Center, Department of Oral Surgery, 1100 Florida Avenue, #127, New Orleans, LA 70119-2799, USA

Received 28 May 2005; accepted 5 June 2005

KEYWORDS Summary A 63-year-old African American male patient presented to the Dental Peripheral; Hygiene Clinic, LSU School of Dentistry for routine hygiene visit. On examination Ameloblastoma; a 1.2 cm red, sessile nodule was noted on the lingual gingiva of the cuspid–bicuspid Surface; left mandibular region. The patient mentioned he had noticed it a few months ago Epithelium and did not seek care as it was asymptomatic. The lesion was covered by normal mucosa, had a smooth surface, and a ﬁrm consistency. All the involved teeth tested vital. Radiographic examination of the area involved did not demonstrate any bony destruction. A biopsy was performed under local anesthesia and the microscopic examination revealed ameloblastic growth with an intact layer of covering non- keratinized squamous epithelium. The tumor islands consisted of a central mass of loosely connected stellate reticulum-like cells surrounded by a layer of columnar cells with well-polarized nuclei. The histological and clinical features were diagnostic for peripheral ameloblastoma. There have been a few well-documented cases of Peripheral ameloblastoma originating in non-tooth bearing regions of the jaw bones. This evidence supports an etiology from surface epithelium. c 2005 Elsevier Ltd. All rights reserved.

Introduction 1959, Stanley and Krogh deﬁned the clinical and histopathologic characteristics.3 It is typically a 4 Peripheral ameloblastoma (PA) is a rare odonto- slow, benign, single, sessile, asymptomatic lesion. genic tumor that accounts for 1% for all ameloblas- Histologically, this lesion is identical to the classic tomas.1 Kuri ﬁrst reported PA in 1911.2 In intraosseous ameloblastoma but appears exclu- sively in the oral mucosa over the alveolar pro- cesses of both jaws.4 Radiographic studies usually * Tel.: +1 504 619 8524. are negative for any bony destruction of inva- E-mail address: [email protected] sion except for saucerization of the underlying

1741-9409/$ - see front matter c 2005 Elsevier Ltd. All rights reserved. doi:10.1016/j.ooe.2005.06.001 212 K. Shetty periosteum.4 The etiology of PA is unclear. The tumor can derive from the extraosseous epithelial remnants of the dental lamina or from the basal cell layer of the oral mucosa, which is believed to have odontogenic potential.5 The differential diagnosis usually includes pyogenic granuloma, peripheral giant cell granuloma, peripheral odontogenic ﬁbroma, peripheral ossifying ﬁbroma, papilloma, and epulis. The purpose of this paper is to present an additional case of PA and to review the current literature.

Case report Figure 2 Occlusal mandibular panoramic radiograph A 63-year-old African American male patient pre- showing no evidence of any Osseous involvement. sented to the Dental Hygiene Clinic, LSU School of Dentistry for routine hygiene visit. On examination a 1.2 cm red, sessile nodule was noted on the removal of the lesion with curettage and peripheral lingual gingiva of the cuspid–bicuspid left mandib- ostectomy. The post-operative course was ular region (Fig. 1). The patient mentioned he had uneventful. noticed it a few months ago and did not seek care as it was asymptomatic. The lesion was covered by normal mucosa, had a smooth surface, and a ﬁrm Review of literature consistency. All the involved teeth tested vital. Radiographic examination of the area involved did A review of the English literature disclosed 66 well- not demonstrate any bony destruction (Fig. 2). A documented cases of PA. Nauta et al.4 had re- biopsy was performed under local anesthesia and viewed 52 cases that had been previously the microscopic examination revealed ameloblas- published. Since then Redman et al.6 reviewed tic growth with an intact layer of covering non-ker- and reported four additional cases. Seven cases atinized squamous epithelium (Fig. 3A). The tumor were reported by Gurol and Burkes,7 one case by islands consisted of a central mass of loosely con- Califano et al.,8 two cases by Orsini et al.,9 and nected stellate reticulum-like cells surrounded one case by El-Hakim and El-Khashab10 We have by a layer of columnar cells with well-polarized presented three additional cases in this paper for nuclei (Fig. 3B). The histological and clinical fea- a total of 70 cases. Zhu et al.11 have published tures were diagnostic for peripheral ameloblas- and reviewed a total of 43 cases of PA in the toma. The patient underwent complete surgical Japanese literature between 1967 and 1995. Nauta et al.4 reviewed or presented 52 cases of peripheral ameloblastoma and cases of basal cell carcinoma of the gingiva and PA. Histologically both of these lesions appear to be identical and were considered the same entity. The ages of the patients ranged from 16 to 92 years with a mean age of 50.2 years. About 50% of the lesions occurred between the ages of 40 and 60. Thirty-four cases (65%) occurred in the mandible; 18 (35%) were in the maxilla. There was no difference in location between the left and right side of the jaws. For lesions in the maxilla, the primary site was the maxillary tuberosity; for those in the mandible, it was the lingual area of the premolars. Of the 52 cases, 19 (37%) were female, 31 (60%) were male, and no gender was reported in two cases. Figure 1 A red, sessile nodule was noted on the lingual The average size of the lesion measured between gingiva of the cuspid–bicuspid left mandibular region. 1 and 2 cm with only a few cases showing evidence Peripheral ameloblastoma: An etiology from surface epithelium? 213

Figure 3 (A) Photomicrograph demonstrating areas consistent peripheral ameloblastoma originating from a surface epithelium (H and E stain, 40·). (B) Photomicrograph demonstrating the tumor islands consisting of a central mass of loosely connected stellate reticulum-like cells surrounded by a layer of columnar cells with well-polarized nuclei (H and E stain, 100·).

of minor radiographic bone resorption. Although alveolar bone and histological presence of mitotic there was no stratification of the cases into the activity. Mitotic figures are usually representative type of ameloblastoma, the case presented in this of rapid growth, but ameloblastomas are regarded paper was follicular in nature. The treatment of as relatively slowly growing odontogenic tumors. choice was local excision including a 1–2mmmar- The report of PA in the elderly is relatively gin of healthy tissue. Local recurrence was re- infrequent. Actually, this is the second oldest ported to be 16% with an average follow up of case reported throughout the English literature. about 3 years. The predominant histological pattern was folli- Redman et al.6 documented another example of cular. PA. This unusual presentation of PA was in the Califano and Burkes7 reported a single case of retromolar pad of an 84-year-old male, with radio- PA. The patient was a 47-year-old male with a mass graphic evidence of saucerization of the underlying in the canine region of the maxilla of about 3 cm in 214 K. Shetty diameter. The biopsy report revealed a trabecular was the mandible (70% of all lesions) with the pre- architectural growth pattern. The lesion had malig- molar region being the most prevalent. The maxilla nant characteristics of a high mitotic index and comprised 28% of all lesions with the anterior re- perineural infiltration. Surgical resection of the gion as the preferred site. The clinical presentation upper left maxilla was performed with excision of of PA in the Japanese literature was similar to that bone surrounding the tumor. No recurrence re- of the English literature. Stratification of the histo- ported after a follow up of 12 months. logical diagnosis showed 19 cases of acanthoma- Gurol et al.8 reported seven cases of PA. One fe- tous PA, 7 plexiform PA, 3 follicular PA, and 4 male patient had two lesions. The average age of mixed PA. Further microscopic analysis of 30 PA the patients was 62 years, four of which were male cases revealed a continuity between the surface and three female. Five mandibular lesions were epithelium and the tumor nests in 22 cases, and a identified: three in the premolar gingiva, area, zone of connective tissue between the tumor and one in the incisal gingival and one in the molar re- the superficial epithelium in eight cases. Zhu gions. The remaining three maxillary lesions were et al.11 presented findings suggesting that oral epi- all found in the molar gingival sites. The lesions thelium has the potential to differentiate into were removed by surgical excision with no recur- ameloblasts and to form teeth and odontogenic rence. Histologically, three lesions were diagnosed lesions. as acanthomatous, two as follicular, and three as In conclusion, a rare case of peripheral amelo- plexiform. blastoma in a non-tooth bearing region of the jaw Orsani et al.9 reported two cases of PA. The first bone is presented with a review of literature.This patient was a 49-year-old male with a 2.5 cm diam- evidence supports an etiology from surface epithe- eter lesion in the premolar–molar left mandibular lium. In fact, there is term peripheral ameloblas- region. A definitive diagnosis of follicular type PA toma should include lesions found in more remote was given. Surgical resection including a small mar- locations such as the buccal mucosa, lips, palate, gin of normal surrounding tissue was performed. and other parts of the oral mucosa. The second case was in a 46-year-old patient with a 1.5 cm lesion in the mandibular premolar–molar site. Biopsy revealed a plexiform type PA. No References recurrences were observed for 7 years and 4 years, respectively, after surgical excision of the lesion. 1. Neville BW, Damm DD, Allen CM, Bouquot JE. Oral & El-Hakim and El-Khashab10 reported an unusual maxillofacial pathology. Pennsylvania: W.B. Saunders case of PA in conjunction with a mural ameloblas- Company; 1995, p 519. toma developing from the lining of a dentigerous 2. Kuru H. Ueber das adamantinoma. Zentralbl Allg Pathol 1911;22:291. cyst related to an impacted mandibular canine in 3. Stanley HRJ, Krogh HW. Peripheral ameloblastoma: a 13-year-old boy. A definitive diagnosis of plexi- report of a case. Oral Surg Oral Med Oral Pathol 1959;12: form PA was given. An en bloc resection with safety 760–5. margins was performed. No evidence of recurrence 4. Nauta JM, Paunders AK, Schoots CJF, Varmey A, Rooden- after 6 years was reported. burg JLN. Peripheral ameloblastoma. A case report and review of literature. Int J Oral Maxillofac Surg 1992;21: Only four cases of malignant PA have been re- 40–4. 14 ported to date. Edmondson et al. was the first 5. Buchner A, Scuibba JJ. Peripheral epithelial odontogenic to report a case of PA with malignant transfor- tumors: a review. Oral Surg 1987;63:688. mation. Song-Chyr et al.13 documented the only 6. Redman RS, Keegan BP, Coleman JS, Patterson RH. Periph- malignant PA that metastasized. The supra-clavi- eral ameloblastoma with unusual mitotic activity and conflicting evidence regarding histogenesis. J Oral Maxillo- cular lymph nodes were the site of metastasis. fac Surg 1994;52:192–7. 12 McClatchey et al. showed a PA carcinoma local- 7. Guraol M, Burkes EJ. Peripheral ameloblastoma. J Peri- ized in the maxillary tuberosity. Baden et al.15 re- odontal 1995;66:1065–8. ported a malignant transformation of PA with 2 8. Califano L, Maremonti P, Boscaino G, De Rosa CG. Periph- recurrences over a 5-year period, once as a squa- eral ameloblastoma: report of a case with malignant aspect. Brit J Oral Maxillofac Surg 1996;34:240–2. mous cell carcinoma and again as an undifferenti- 9. Orsini G, Massimilliano F, Rubini C, Piatelli A. Peripheral ated carcinoma. ameloblastoma: a report of 2 cases. J Periodontol 2000; Zhu et al.11 did a comprehensive review of the 71:1174–6. Japanese literature and found 43 cases, which 10. El-Hakim IE, El-Khashab MM. Peripheral and mural amelo- spanned a wide age range of 9–89 with the major- blastoma in the mandibular canine region of a 13 year old boy. J Oral Maxillofac Surg 2000;58:1150–4. ity of cases occurring in the 5[th] and 7[th] dec- 11. Zhu EX, Okada N, Takagi M. Peripheral ameloblastoma: case ades. Male patients comprised 70% (30 cases) and report and review of literature. J Oral Maxillofac Surg 1995; females 30% (13 cases). The most common site 53:590–4. Peripheral ameloblastoma: An etiology from surface epithelium? 215

12. McClatchey EC, Sullivan MJ, Paugh DR. Peripheral amelob- 14. Edmondson HD, Browne RM, Potts AJC. Intraoral basal cell lastic carcinoma: a case report of a rare neoplasm. J carcinoma. Br J Oral Surg 1982;20:239–47. Otolaryngol 1989;18:109–11. 15. Baden E, Doyle J, Petriella V. Malignant transformation of 13. Song-Chyr L, Chen-Mei L, Liang-Jiuans H, Hsueh-Wan K. peripheral ameloblastoma. Oral Surg Oral Med Oral Pathol Peripheral ameloblastoma with metastasis. Int J Oral 1993;75:214–9. Maxillofac Surg 1987;16:202–4.