A clinicopathological study of ameloblastomas

A case report on granular cell ameloblastoma - A rare histological entity

Granular cell ameloblastoma is a rare condition, accounting for 3.5% of all ameloblastoma cases that shows marked transformation in the cytoplasm of tumor cells, which are usually stellate reticulum-like cells. The transformed cells possess very coarse, granular eosinophilic cytoplasm. Granular cell ameloblastoma is aggressive in nature with a marked propensity for recurrence and can progress to metastasis. This article discusses a case report of a 35-year-old female patient diagnosed with granular cell ameloblastoma of the right mandible.

Ameloblastoma with distinctive granular cell pattern: an 8 case study

Ameloblastoma with granular cell pattern (AGC) is classified as an unusual histological subtype of solid/multicystic ameloblastoma, characterized by granular changes in stellate-like cells located within the inner portion of the epithelial follicles. Studies have revealed that lysosomal overload causes cytoplasmic granularity; however, the mechanism involved remains poorly understood. Here we report on eight cases of granular cell ameloblastoma, in the posterior region of the mandible. The age of the patients included in this case series ranged from 35 -64 years old and 87.5% of cases occurred in non-Caucasians, with a slight gender predilection for men (62.5%). There was no evidence of recurrence, and the majority of the cases were treated with surgical resection (87.5%). All tumors displayed histopathological features consistent with the diagnosis of ameloblastoma with granular cell pattern.

"Evaluation of safety margin" in ameloblastoma of the mandible by surgical, radiological, and histopathological methods: An evidence-based study

OBJECTIVE

The purpose of this study is to elicit the amount of safety margin necessary around the ameloblastic lesion in view of preventing further recurrence.

MATERIALS AND METHODS

The study consisted of 25 cases of mandibular ameloblastoma. Diagnosis was based on clinical and radiological analysis and confirmed by histopathological report. An incisional biopsy was done preoperatively to confirm the diagnosis. Segmental resection was planned for all the cases. After the resection, postoperative panoramic radiograph of the specimen was taken followed by histopathological examination of its margin to detect tumor cell infiltration.

RESULTS AND CONCLUSION

In all our cases, the ameloblastoma was infiltrating in nature. A follow-up period of 10 years showed neither recurrence nor implant failure. In our study, we conclude our safe margin for infiltrating variant of ameloblastoma based on histopathological report of the resected specimen.

Ameloblastoma of the anterior mandible

Ameloblastoma or adamantinoma is the rarest of the three forms of tumor of the odontogenic type. They are benign, locally aggressive neoplasms arising from ameloblasts, which typically occur at the angle of the mandible, and are often associated with an un-erupted tooth and must, therefore, be differentiated from a dentigerous cyst which will be centered on the crown. When in the maxilla (less common), they are located in the premolar region, and can extend up in the maxillary sinus. Ameloblastoma is reported to constitute about 1-3% of tumors and cysts of the jaws. The tumor is by far more common in the mandible than in the maxilla and shows predilection for various parts of the mandible in different racial groups. The relative frequency of the mandible to maxilla is reported as varying from 80-20% to 99-1%. Here, we are representing a case of ameloblastoma of anterior mandible which was considered as a rare site of occurrence.

Comparative morphometric study of AgNORs in variants of ameloblastoma

Aims:

To compare the area and number of AgNORs (silver stained nucleolar organizer regions) by morphometry between follicular and plexiform variants of ameloblastoma in order to analyze their cell proliferation rates.

Materials and Methods:

This retrospective study was carried out on 30 cases each of follicular and plexiform ameloblastoma. The sections were obtained and stained with silver staining technique to identify the nucleolar organizer regions. AgNORs were quantified using two parameters; manual tag for the number of AgNORs and area measurement using the image analyzer software, Image-Pro-Express.

Results:

Morphometric area measurements of AgNOR were significantly higher for Plexiform ameloblastoma (0.831μm²) than follicular ameloblastoma (0.528μm²). Enumeration of the number of AgNORs showed a significantly higher number of AgNOR for follicular ameloblastoma (1.71) than plexiform ameloblastoma (1.43). Among the groups studied, follicular ameloblastoma was more aggressive than plexiform ameloblastoma, as it showed smaller AgNOR area and higher AgNOR number.

Conclusion:

The combination of counting the number and measuring the area of AgNOR dots showed a significant overall difference between AgNOR profiles of follicular and plexiform variants of ameloblastoma.

Surgical management of ameloblastoma: Conservative or radical approach

AIM

The ameloblastoma is a benign odontogenic tumor of epithelial origin that exhibits a locally aggressive behavior with a high level of recurrence, being believed theoretically to come from dental lamina remains, the enamel organ in development, epithelial cover of odontogenic cysts or from the cells of the basal layer of the oral mucosa. Especially larger, aggressive lesions require a more radical surgical approach resulting in large jaw defects. This paper discusses our experiences in the management of ameloblastoma tumor in 20 such patients.

MATERIALS AND METHODS

A review of 20 cases of ameloblastoma (6 in the maxillary and 14 in the mandibular region) is presented. The lesions were between 4 and 8 cm in diameter. The methods of treatment consisted of radical surgery (i.e., segmental resection) and conservative treatments (i.e., enucleation with bone curettage). Half the cases were treated conservatively and others surgically.

RESULTS

Enucleation with curettage was done in 10 cases, out of which six (60%) showed recurrence, whereas one (10%) case in the surgical group showed recurrence. Relatively higher tendencies of recurrence were observed in the cases treated conservatively. The aesthetic and functional outcomes were satisfying in all patients.

CONCLUSION

According to our opinion, radical surgical resection of ameloblastoma is the treatment of choice, followed by the reconstruction of the defects, allowing good functional and aesthetic outcome.

Basal cell ameloblastoma-review of literature with report of three cases

The ameloblastoma is the most common epithelial odontogenic tumor of the jaw with several histologic variants viz. follicular, plexiform, acanthomatous, desmoplastic, and granular cell and basal cell types. The basal cell ameloblastoma is a rare histological variant which tends to demonstrate microscopic features similar to cutaneous basal cell carcinoma and basaloid squamous cell carcinoma. In the current article we report three cases and review the literature of this rare tumor.

Ameloblastoma: an evidence based study

OBJECTIVE

The purpose of this study is to present a series of 46 cases of ameloblastoma-38 in mandible and 8 in maxilla treated in the Oral and Maxillofacial Surgery Department of Government Dental College and Hospital, Nagpur during 1997-2006 with emphasis on various treatment modalities used in treating different types of ameloblastoma and how to define the safe margin for different clinical and histopathological types of ameloblastoma with their follow-up.

METHOD

Confirmation of lesion done by incisional biopsy upon which treatment plan was decided and if resection is done then section was studied for amount of infiltration in adjoining bone histopathologically.

RESULT

In a follow-up period of 1-9 years recurrence was observed in six cases, two in patients treated with enucleation and curettage, three in patients treated with segmental resection and one in patient with peripheral ameloblastoma treated with soft tissue resection.

CONCLUSION

From this study we conclude that depending upon the histopathological type different amount of adjoining bone is resected to get the safe margin and based upon the result it is recommended to remain a bit aggressive in maxillary lesions.

A clinico-pathological comparison between mandibular and maxillary ameloblastomas in Sri Lanka

BACKGROUND

The aim of this retrospective study was to analyse the relative prevalence and the clinico-pathological characteristics of mandibular and maxillary ameloblastomas in Sri Lanka.

METHODS

Clinico-pathological features of a total of 286 cases of ameloblastomas were analysed.

RESULTS

Out of the 286 cases, 87.8% (251/286) of ameloblastomas occurred in the mandible, while 10.8% (31/286) occurred in the maxilla indicating a ratio of 8:1. In the mandible, 54% (136/251), 40% (100/251) and 6% (15/251) of tumours and in the maxilla, 23% (7/31), 48% (15/31) and 29% (9/31) of tumours were solid/multicystic ameloblastomas (SMA), unicystic ameloblastomas (UA) and desmoplastic ameloblastomas (DA) respectively. No gender predilection was observed in mandibular or maxillary ameloblastomas. Most of the lesions were observed in 2nd to 5th decade of life (mean age 33.2 years). No differences between mandibular and maxillary ameloblastomas were observed with reference to overall cellularity and mitotic activity. Solid/multicystic and UAs showed a predilection to posterior region, while DAs were frequently found in the anterior region of both jaws. Twenty-one percentage (60/286) of ameloblastomas presented with recurrences, and 94% (34/36) of these recurrences were observed in cases treated conservatively.

CONCLUSION

In conclusion, mandibular ameloblastomas were more prevalent than maxillary ameloblastomas, while no differences were observed in age or gender distribution between the mandibular and maxillary ameloblastomas. However, higher proportion of DAs and UAs was observed in the maxilla compared with some of the other studies. SMA should be treated with resection to prevent recurrences.

Vergleichende klinische und immunhistochemische Charakterisierung keratozystischer odontogener Tumoren und Ameloblastome im Hinblick auf das Rezidivrisiko

BACKGROUND

With the new term "keratocystic odontogenic tumour" (KCOT) keratocyts are even in the nomenclature a close differential diagnosis to ameloblastomas (A).

PURPOSE

Recurrence of KCOT and A were retrospectively compared with regard to treatment and immunohistochemical markers of cell cycle and migration and cell architecture.

PATIENTS AND METHODS

Biopsies harvested over a period of 22 years of 101 patients (86 KCOT, 15 A) were examined. The histopathological slides were stained with H&E and with the immunohistochemical markers: Cyclin D1, Collagen IV, p16, Cox-2-Laminin-5 and Tenascin-C.

RESULTS

Mean age KCOT 47 years (range 14-80 years), A 41 years (range 16-79 years). Gender KCOT: m:f =2:1; A: m:f = 3:2. Region of origin mandible with predilection of the angle and the ramus: KCOT: 76; A: 12. Maxilla: KCOT: 18; A: 3. Multiple lesions were found in 5 KCOT patients. Treatment primary KCOT: cystectomy (46), cystostomy (6), cystectomy and curettage (17), cystectomy and marginal ostectomy (14), resection (11). A: resection (10), enucleation (5). Recurrence rate KCOT: 11,7% after 5,5 years. Recurrence after: cystostomy (4), cystectomy (6), cystectomy and curettage (3), cystectomy and marginal ostectomy (2). A: no recurrences. Immunohistochemistry Cell cycle associated and extracellular matrix proteins did not differ in quantity in KCOT and A, and did also not differ in recurrent and non-recurrent KCOT.

CONCLUSIONS

1. KCOT are in the own cohort more likely recurrent than A. 2. Recurrence rate of KCOT can not be predicted by the used (most common) markers of cell cycle, migration and modulation of architecture. 3. Higher recurrence rate of KCOT in the patients examined is proposed due to less extensive resection.

Extensive ameloblastoma of the jaws: surgical management and immediate reconstruction using microvascular flaps

OBJECTIVE

Ameloblastoma is a rare histological benign but locally aggressive tumor with a marked tendency for recurrence. Especially larger, aggressive lesions require a more radical surgical approach resulting in large jaw defects. The purpose of this study is to analyze the long-term functional and esthetic results after immediate reconstruction of large jaw defects using microvascular flaps.

STUDY DESIGN

A review of 7 cases of giant ameloblastoma (2 in the maxillary and 5 in the mandibular region) is presented. The lesions were between 4 and 8 cm in diameter. All patients were treated by a radical surgical protocol. All cases were immediately reconstructed using microvascular grafts from either the scapula or the iliac crest bone. Dental implants were inserted in all patients after removal of the osteosynthesis material.

RESULTS

All patients were prosthetically rehabilitated. All implants survived throughout the observation time. The esthetic and functional outcomes were satisfying in all patients. No case of recurrence of the tumor could be observed so far.

CONCLUSION

According to our opinion, immediate reconstruction is the treatment of choice after radical surgical excision of ameloblastoma. This 1-step procedure decreases the number of surgeries and allows earlier prosthetic rehabilitation.

Surgical Management of Ameloblastoma in the Mandible: Segmental Mandibulectomy and Immediate Reconstruction With Free Fibula or Deep Circumflex Iliac Artery Flap (Evaluation of the Long-Term Esthetic and Functional Results)

PURPOSE

Ameloblastoma is responsible for 1% of all the oral and maxillomandibular cysts and tumors. It is odontogenic in origin and benign in nature but it has a high percentage of local recurrence rate and possible malignant development when treated inadequately. With the advancement of craniofacial surgical techniques, use of free flaps for mandibular reconstruction, and dental rehabilitation (such as osseointegration), the segmental mandibulectomy and immediate reconstruction with free flaps are beginning to be used more effectively for the treatment of the mandibular ameloblastoma. The aim of this article is to evaluate the clinical results of the patients with mandibular ameloblastoma who were treated with segmental mandibulectomy and immediate reconstruction with free flaps.

PATIENTS AND METHODS

We present 11 patients who had segmental mandibulectomy and immediate reconstruction with free deep circumflex iliac artery or fibular flap for treatment of mandibular ameloblastoma. The average age of the patients was 25.4 years (range, 18-38 years). The patients were followed up for a mean of 29.3 months (range, 17-38 months). The functional and esthetic results were also evaluated by using a questionnaire in the long term. The questionnaire consisted of questions addressing oral continence, diet, social activities, speech, and facial appearance.

RESULTS

All flaps survived totally. Recurrence was not detected during the follow-up period. It was found that all patients had good esthetic and functional results after immediate reconstruction. The social activities of patients also were not affected after treatment.

CONCLUSIONS

We experienced that segmental mandibulectomy with safe borders and immediate reconstruction with free fibula flap or deep circumflex iliac artery (DCIA) flap is an ideal treatment method for mandibular ameloblastoma. The functional and esthetic results are also detected as very satisfactory for the patients.

Ameloblastoma in the Hong Kong Chinese. Part 1: systematic review and clinical presentation

OBJECTIVES

The aim of Part 1 of this study was to determine the clinical presentation of central ameloblastomas in the Hong Kong Chinese and to compare them with other reported series by a systematic review (SR).

METHODS

The study had two elements, that of a complete series of all ameloblastomas presenting at a major Chinese maxillofacial surgical unit as well as a SR. The files of the Department of Oral and Maxillofacial Surgery of the University of Hong Kong between 1989 and 2000 were reviewed for ameloblastoma cases. The relevant literature was identified by electronic databases, review of citation lists and hand searching of key journals. The principal selection criterion was that the study should represent a complete collection of cases.

RESULTS

Fifty-three published series of cases were included in the SR. They generally reported little more than sex, mean age and range, and affected jaw. Only 16 studies considered recurrence. Sixty-one cases of ameloblastoma were identified in the present study. There were 30 males and 31 females, contrary to the predilection for males in other reports. Eighty-four percent of cases were found in the mandible, agreeing with the SR. The mean age at first presentation was 30.5 years, lower than that of the SR; only a Korean report and a small Bangladeshi report showed younger presentation. The present report had the shortest period between first becoming aware of the lesion and seeking treatment; this period was significantly shorter for younger patients. Although the present study was in agreement with the SR with regard to swelling, this study reported a significantly higher proportion of patients presenting with pain.

CONCLUSION

Although the presentation of ameloblastoma within this Chinese community was broadly similar to that observed in other populations, it differed in a number of important respects. It had a younger age at first presentation than many other communities, including other Orientals; it was associated with a shorter period between first becoming aware of the lesion and seeking treatment, particularly in the young; and it was more frequently associated with pain than in the SR.

Mandibular ameloblastoma: analysis of surgical treatment carried out in 60 patients between 1977 and 1998

Ameloblastoma, a benign tumor of odontogenic type, represents 10% of all tumors of the jawbone. It is localized in the mandible in 80% of cases and in the upper jaw in the remaining 20%. In every case, the selection of the surgical treatment to be applied must consider some fundamental elements, including the age and general state of health of the patient, the clinicopathological variant, and the localization and extent of the tumor. In addition, it is necessary to evaluate whether the neoplasm to be treated is a primitive lesion or a recurrence. Although ameloblastoma has relative histological characteristics of benignity, this neoplasm has a high percentage of local recurrence and possible malignant development when treated inadequately. The aim of this study was to carry out a follow-up of 60 patients treated for ameloblastoma of the mandible between 1977 and 1998, analyzing the problems faced in removing this benign neoplasm and those concerning reconstruction of the surgical defect.

Ameloblastoma with mucous cell differentiation

The finding of pale or clear cells in ameloblastomas is an exceptionally rare--but not unreported--phenomenon. The diagnostic implications of the presence of such cells in ameloblastomas are several and relate mainly to the question of histopathologic differential diagnosis. Although mucous cells in ameloblastomas are an accepted phenomenon, their occurrence has been reported only infrequently. This report describes a case of ameloblastoma exhibiting histopathologic evidence of focal mucous cell differentiation. Issues relating to the differential diagnosis of this lesion are discussed.

Effect of preservation of the inferior and posterior borders on recurrence of ameloblastomas of the mandible

OBJECTIVE

The purpose of this study was to evaluate the experience and results of using a rational radical conservative approach in the surgical treatment of mandibular ameloblastomas.

STUDY DESIGN

A retrospective analysis of every patient with an ameloblastoma of the mandible treated in the Department of Oral Medicine and Oral Surgery at the Jordan University of Science and Technology between 1989 and 1999 was conducted. All were operated on by the author, who used a uniform surgical protocol in every case. All soft tissues in contact or overlying the lesion and a wide margin of cancellous bone related to the tumor were destroyed. The compact bone comprising the lower border of the mandible and the posterior border of the ascending ramus together with the nutrient periosteum attached to them were preserved, thus maintaining the continuity of the mandible and the facial contours. When teeth, soft tissues, or both were involved, they were destroyed. All patients were reviewed annually for a follow-up period of 3 to 10 years (mean, 6.5 years) by the same clinician.

RESULTS

All ameloblastomas were located in the mandible; 21 were in the angle/molar region and the ascending ramus, and 2 cases were in the anterior region. There was no clinical or radiographic evidence of recurrence observed during the follow-up period.

CONCLUSION

Ameloblastoma has a high rate of local recurrence if it is not adequately removed. The findings of this study to date suggest that the technique of rational radical conservative resection may have a place in the treatment of ameloblastoma of the mandible and is worthy of further trial.

Ameloblastoma: the Zimbabwean experience over 10 years

OBJECTIVES

A review of 117 ameloblastomas treated over a 10-year period was carried out.

STUDY DESIGN

Clinical records of 117 patients treated for histologically diagnosed ameloblastoma were retrieved and analyzed for age, sex, anatomic distribution, duration of lesions, clinical features, and treatment methods with results and complications.

RESULTS

Men and women were equally affected. The average age at the time of presentation was 28 years; 95.7% of the ameloblastomas occurred in the mandible; and 59% occurred in the premolar/incisor/canine region.

CONCLUSION

Ameloblastoma occurs predominantly in the anterior mandible with equal frequency in men and women. Wide resection reduces recurrence.

Clinical features and management of ameloblastoma of the mandible in children and adolescents

Thirty cases of ameloblastoma of the mandible in children and adolescents were reviewed. During the period of evaluation, 206 patients with ameloblastoma in the craniofacial region were seen of which 14.6% were in children (under 18 years). The tumour was more prevalent in male (1.5:1). Enucleation with curettage of the surrounding bones appears adequate for unicystic lesions. Multicystic lesions were managed by radical resection of the mandible with or without immediate reconstruction of defect with bone graft or by resection of the lesion with the dentoalveolar structure and preservation of the lower border of the mandible. Uninvolved periosteum should be preserved because of its osteogenic potential.

Infrequent clinicopathological findings in 108 ameloblastomas

One hundred and eight ameloblastomas diagnosed in a rural black Africa population were analysed for clinicopathologic findings other than those classically described. One patient had a polycystic ameloblastoma adjacent to an ameloblastic fibroma. Two other polycystic ameloblastomas showed aneurysmal bone cyst formation and one mandibular tumour was diagnosed as a keratoameloblastoma. Microscopic changes resembling an adenomatoid odontogenic tumour were present in association with two unicystic ameloblastomas and a HPV18-positive verrucous lesion occurred in the lining of a cystic space of a polycystic ameloblastoma. Two ameloblastomas contained eosinophilic granules in all tumor cells and melanocytes were diffusely present in another. One case exhibited a focus of mucous cell metaplasia. Two polycystic ameloblastomas showed diffuse interstitial ossification. One mandibular tumor was diagnosed as a desmoplastic ameloblastoma and another as an odontoameloblastoma. This study demonstrated that although ameloblastomas are regarded as a fairly homogeneous group of neoplasms, detailed investigations prove clinicopathologic diversity in a significant number of lesions.

Ameloblastoma: biological profile of 3677 cases

Available literature on ameloblastoma of the jaw was reviewed, including publications from 1960 to 1993, and compared to the latest larger review, published by Small and Waldron in 1955. The average age of patients with ameloblastoma is 36 years. In developing countries ameloblastomas occur in younger patients. Men and women are equally affected. Women are 4 years younger than men when ameloblastomas first occur, and the tumours appear to be larger in females. Dominant clinical symptoms such as painless swelling and slow growth are non-characteristic. The ratio of ameloblastoma of the mandible to maxilla is 5 to 1. Ameloblastomas of the mandible occur 12 years earlier than those of the maxilla. Ameloblastomas occur most frequently in the molar region of the mandible. In Blacks, ameloblastomas occur more frequently in the anterior region of the jaws. Radiologically, 50% of ameloblastomas appear as multilocular radiolucent lesions with sharp delineation. Histologically, one-third are plexiform, one-third follicular; other variants such as acanthomatous ameloblastoma occur in older patients. Two percent of ameloblastomas are peripheral tumours. Unicystic ameloblastomas occurring in younger patients have been found in 6%. Detailed data on 345 patients with ameloblastoma were evaluated for clarification of therapeutic approaches. Chemotherapy and radiation seem to be contraindicated. Ameloblastomas of the maxilla should be treated as radically as possible, ameloblastomas of the mandible should also be treated radically. However, ameloblastomas which radiologically appear as unilocular lesions may be treated conservatively (enucleation, curettage), whenever all areas of the cystic lumen are controllable intraoperatively. Unicystic ameloblastomas occurring in patients 15 years younger than those with multisystic ameloblastoma may be treated conservatively except in cases with invasion of epithelium into the cyst wall. Different recurrence rates have been found for histological variants of the ameloblastoma. Follicular ameloblastomas appear to recur more often than the plexiform type. Unicystic ameloblastomas reveal lower recurrence rates than "non-unicystic" ameloblastomas. The peripheral type of ameloblastoma may be excised, since conservative therapy results in low recurrence rates. Postoperative follow-up is most important in the therapy of ameloblastoma, because more than 50% of all recurrences occur within 5 years postoperatively.

Ameloblastoma: clinical features and management of 315 cases from Kaduna, Nigeria

This paper reviews 315 cases of ameloblastoma seen and managed at the Oral and Maxillofacial Clinic of Ahmadu Bello University Hospital, Kaduna, Nigeria over a 20-year period. The data collected on age at presentation, sex distribution, clinical presentation and modalities of treatment are analysed and discussed. A male preponderance was found, with peak presentation in the third and fourth decades of life. Few patients presented with mucosal ulceration, while some presented atypically with expansion of either the lingual or buccal cortical plate of the mandible. Resection of the lesion with dento-alveolar bone and preservation of the lower border of the mandible is effective conservative management in patients with an intact lower border. We do not recommend curettage or enucleation because of the frequency of recurrence. One hundred percent success was recorded in the patients rehabilitated using autogenous bone grafts. Where practicable, bone grafting should be done immediately to avoid the common complications of displacement of bony remnants and occlusal disharmony that occur when grafting is delayed.

The desmo- and osteoplastic ameloblastoma. Histologic variant or clinicopathologic entity? Case reports

Two cases of desmoplastic ameloblastoma (DA) are presented, bringing the total number of reported cases to 29. One case of the so-called "hybrid lesion" is added to the presentation. Immunohistochemical studies indicate that the desmoplasia is caused by active de novo synthesis of extracellular matrix proteins. Moreover, the DA may also show osteoplasia, and this probably explains the characteristic radiographic appearance of many DAs, i.e. the occurrence of both radiolucent and radiopaque changes, suggestive of a fibro-osseous lesion. Many more cases of DA are needed to clarify the true nature of this most interesting tumor.

Granular cells in odontogenic and non-odontogenic tumours

Granular cells can occur in various odontogenic and non-odontogenic tumours. 5 granular cell lesions, one granular cell ameloblastoma, one so-called granular cell ameloblastic fibroma and three granular cell tumours were examined immunohistochemically for the intermediate filaments cytokeratin, vimentin, desmin, neurofilaments and the neural markers NSE and S-100 protein. The granular cell tumors (granular cell myoblastoma) showed positive staining for vimentin and S-100 protein. Only vimentin could be demonstrated in the granular cells of the so-called granular cell ameloblastic fibroma, whereas the granular cell ameloblastoma showed positive staining only for cytokeratin. A positive reaction with S-100 protein was not found in any of the odontogenic tumours. In our opinion the mesenchymal odontogenic granular cell is a fibroblast, whereas the epithelial granular cell is derived from enamel epithelium. The term "granular cell ameloblastic fibroma" is a misnomer, as a number of these tumours are probably central odontogenic fibromas exhibiting granular cell transformation.

Late loco-regional recurrences after radical resection for mandibular ameloblastoma

5 cases of mandibular ameloblastoma are described with multiple recurrences after a long period of time. 4 of them were primarily treated by radical resection. 1 was initially treated by enucleation and extensive resection was performed only after its recurrence. The invasive growth of the recurrent tumor into the soft tissues and the cranial base, necessitating extensive ablative and reconstructive surgery, reflects the potential aggressiveness of this tumor. It is therefore recommended, to plan an adequate resection in cases of multicystic ameloblastoma, which includes a margin of at least 1 cm, of apparently non-invaded bone. If the tumor has eroded through the cortical bone and invaded into the soft tissues, wider margins are necessary to eliminate possible tumor extensions that are left behind. Adequate follow-up on a regular basis should enable the clinician to detect early recurrence so as to avoid major surgery.