Clear-cell ameloblastoma of the
mandible (a case report)
O. Odukoya ~, O. Arole 2 1Department of Oral Biology and Oral Pathology, College of Medicine of the University of Lagos, Lagos, Nigeria, and 2Oral and Maxillofacial Unit, Dental Centre, General Hospital, Lagos, Nigeria
O. Odukoya, O. Arole: Clear-cell ameloblastoma o f the mandible (a case report). Int. J. Oral Maxillofac. Surg. 1992; 21: 358-359. © Munksgaard 1992 Abstract. An ameloblastoma with histologic evidence of clear cells in a 15-yearold Nigerian male patient, who presented with a slow-growing, intraosseous, anterior mandibular swelling, is reported. The lesion was treated by surgery alone, and has not shown any recurrence 5 years after initial surgery.
WALDRONet al. 3 were the first to report the clear-cell variety of intraosseous ameloblastoma. An additional intraosseous case of clear-cell ameloblastoma has been reported by MULLER & SLOOTWEG I. The occurrence of clear-cell ameloblastoma as an extraosseous lesion has been recently reported by NG & SIAR2. In view of the opinion of WALDRON et al. 3 that this variant of ameloblastoma should be regarded as a low-grade malignant neoplasm, and also in view of the fact that aggressive surgical management of these cases has been suggested, there is a need to document more cases of this variant of ameloblastoma. Case report A 15-year-old Nigerian male patient presented at the Oral and Maxillofacial Surgery Clinic of the Dental Centre, General Hospital, Lagos, with a progressively enlarging, painful swelling of the anterior part of the mandible of 3 months' duration. There were no associ-
Fig. 1. Specimenof mandible removed from patient. Note that in the anterior mandibular region, the lesion extendsmore linguallythan labially.
ated lesions or symptoms elsewhere in the body. Clinical examination showed a wellnourished patient with a partly fluctuant, partly firm mandibular mass, which expanded the bone, and extended from the left mandibular second molar to the right mandibular second premolar. There was bucco-lingual and labio-lingual expansion of the mandibular cortical bone. Radiographs showed an irregular bone destruction and truncation of the roots 0f related teeth. A clinical diagnosis of ameloblastoma was made, and an excisional biopsy was planned. Under general anaesthesia administered through nasoendotracheal intubation, a complete surgical excision of the affected part of the mandible was performed with little surgical ablation of the related neighbouring tissue. The lost part of the mandible was immediately replaced with Kirschner wire, vacuum drainage was inserted, and the wound was closed in layers. Before leaving the theatre, the patient had a naso-
Fig. 2. Photomicrograph of lesion showing hyperplastic surface epithelium (top part) apparently continuous in areas with proliferating folliclesof ameloblastomatous cells. Note also cystic degeneration in some follicles(HE x 25).
Key words: odontogenic tumour; ameloblastoma; clear-cell ameloblastoma. Accepted for publication 18 August 1992
gastric tube inserted and was later fed through this tube. The drainage was removed 48 h postoperatively. The would healed uneventfully within two and a half weeks, after which the patient was returned to normal oral fluid diet. The surgical specimen removed at operation was sent for microscopic examination. The patient was eventually dis-
Fig. 3. High magnification showing follicles of ameloblastomatous cells, columnar, ameloblast-like cells with a clear cytoplasm, and clear cells in central areas of follicle. Note also presence of mitotic figure amidst closely packed cells in centre of one follicle. Prominent nucleoli are visible in many of the cells (HE x 250).
Fig. 4. High-power magnification showing clear cellsin both peripheral and central areas of folliclesof ameloblastoma. Note also hyalinization of connective tissue (HE x 400).
Ameloblastoma o f mandible charged and has been followed clinically on a 3-monthly basis at the outpatient clinic. There has been no recurrence 5 years after the surgery.
malignant ameloblastoma, but, after review, this was interpreted as ameloblastic carcinoma. Discussion
Histopathology
The surgical specimen contained the resected part of the jaw from distal to left mandibular second molar and distal to the right second premolar. The lesion extended more lingually than labially or buccally (Fig. 1). Microscopic examination of multiple sections from the surgical specimen showed a dysplastic, parakeratotic, acanthotic, stratified, squamous epithelium overlying dense fibrous connective tissue infiltrated by follicles, nests, and anastomosing islands of neoplastic, odontogenic epithelial cells. These cells were continuous in areas with the overlying surface epithelium. The neoplastic follicles showed regular ameloblastomatous formations, while some showed clear cells in both the peripheral ameloblast-like cells and the central cells, where stellate reticulum-like cells are normally found. Cystic degeneration of the central cells was noted in some follicles. The ameloblastomatous tumour cells showed occasional mitoses, pl~0mifient nucleoli, and inductive effects on adjacent connective tissue; in areas, they showed penetration into the ne]ghbouring connective tissue (Figs. 2,-4). The stellate, reticulum-like cells were replaced in some areas by spindle cells, while hyperchromatic and pleomorphic tumour cells were seen in other areas. The lesion was initially diagnosed as
The case being reported is interesting for two reasons. Firstly, this is only the fourth reported case of intraosseous ameloblastoma with histologic evidence of clear-cell differentiation, two cases having been reported by WALDRON et al. 3 and one by MULLER & SLOOTV~EG1. Secondly, in spite of a diagnosis of ameloblastic carcinoma following an excisional biopsy, there has been no evidence of recurrence or reported metastasis after a 5-year follow-up. The absence of disease, 5 years after initial surgery, is probably explained by the radical nature of the surgical management applied. This leads us to ask whether this case should have been regarded as that of malignancy in the first instance. The histologic presentation was that of an ameloblastoma with atypical features, qualifying for malignancy. The outstanding feature in the histology was the presence of clear cells. The need to combine such an atypical feature with other features of cellular atypicality before a label of malignancy can be put on this lesion was highlighted in the case of clear-cell peripheral ameloblastoma reported by N 6 & SIAR2. They did not consider their case to be malignant because of the absence of other features of cellular atypicality. The case reported coincides with that of MULLER ~4 SLOOTWEGl in that age and location are the same.
359
The presence of clear cells in an ameloblastoma should not be surprising, because ameloblastomas are supposed to derive from the dental lamina, which has been reported to contain clear cells as one of its components4. The clear cells in clear-cell ameloblastoma have been reported to be rich in glycogenS. A retrospective study of the incidence of clear cells in ameloblastomas and odontogenic carcinomas is presently underway.
Acknowledgment. The authors are grateful to Mrs E O. Oduyoye, of the Department of Oral Biology and Oral Pathology, University of Lagos, for typing the manuscript. References
1. MULLERH, SLOOTWEGP. Celar cell differentiation in an ameloblastoma. J Max.fac Surg 1986: 14: 158-60. 2. NG KH, SIARCH. Peripheral ameloblastoma with clear cell differentiation. Oral Surg 1990: 70: 201-13. 3. WALDRONCA, SMALLIA, SILVERMANH. Clear cell ameloblastoma an odontogenie carcinoma. J Oral Maxillofac Surg 1985: 43: 707-17. 4. WYSOCKIGP, BRANNONRB, GARDNER DG, SAPVP. Histogenesis of the lateral periodontal cyst and the gingival cyst of the adult. Oral Surg 1980: 30: 327-34.
Address: Dr O. Odukoya Department of Oral Biology and Oral Pathology College of Medicine University of Lagos Lagos, Nigeria
mandible (a case report)
O. Odukoya ~, O. Arole 2 1Department of Oral Biology and Oral Pathology, College of Medicine of the University of Lagos, Lagos, Nigeria, and 2Oral and Maxillofacial Unit, Dental Centre, General Hospital, Lagos, Nigeria
O. Odukoya, O. Arole: Clear-cell ameloblastoma o f the mandible (a case report). Int. J. Oral Maxillofac. Surg. 1992; 21: 358-359. © Munksgaard 1992 Abstract. An ameloblastoma with histologic evidence of clear cells in a 15-yearold Nigerian male patient, who presented with a slow-growing, intraosseous, anterior mandibular swelling, is reported. The lesion was treated by surgery alone, and has not shown any recurrence 5 years after initial surgery.
WALDRONet al. 3 were the first to report the clear-cell variety of intraosseous ameloblastoma. An additional intraosseous case of clear-cell ameloblastoma has been reported by MULLER & SLOOTWEG I. The occurrence of clear-cell ameloblastoma as an extraosseous lesion has been recently reported by NG & SIAR2. In view of the opinion of WALDRON et al. 3 that this variant of ameloblastoma should be regarded as a low-grade malignant neoplasm, and also in view of the fact that aggressive surgical management of these cases has been suggested, there is a need to document more cases of this variant of ameloblastoma. Case report A 15-year-old Nigerian male patient presented at the Oral and Maxillofacial Surgery Clinic of the Dental Centre, General Hospital, Lagos, with a progressively enlarging, painful swelling of the anterior part of the mandible of 3 months' duration. There were no associ-
Fig. 1. Specimenof mandible removed from patient. Note that in the anterior mandibular region, the lesion extendsmore linguallythan labially.
ated lesions or symptoms elsewhere in the body. Clinical examination showed a wellnourished patient with a partly fluctuant, partly firm mandibular mass, which expanded the bone, and extended from the left mandibular second molar to the right mandibular second premolar. There was bucco-lingual and labio-lingual expansion of the mandibular cortical bone. Radiographs showed an irregular bone destruction and truncation of the roots 0f related teeth. A clinical diagnosis of ameloblastoma was made, and an excisional biopsy was planned. Under general anaesthesia administered through nasoendotracheal intubation, a complete surgical excision of the affected part of the mandible was performed with little surgical ablation of the related neighbouring tissue. The lost part of the mandible was immediately replaced with Kirschner wire, vacuum drainage was inserted, and the wound was closed in layers. Before leaving the theatre, the patient had a naso-
Fig. 2. Photomicrograph of lesion showing hyperplastic surface epithelium (top part) apparently continuous in areas with proliferating folliclesof ameloblastomatous cells. Note also cystic degeneration in some follicles(HE x 25).
Key words: odontogenic tumour; ameloblastoma; clear-cell ameloblastoma. Accepted for publication 18 August 1992
gastric tube inserted and was later fed through this tube. The drainage was removed 48 h postoperatively. The would healed uneventfully within two and a half weeks, after which the patient was returned to normal oral fluid diet. The surgical specimen removed at operation was sent for microscopic examination. The patient was eventually dis-
Fig. 3. High magnification showing follicles of ameloblastomatous cells, columnar, ameloblast-like cells with a clear cytoplasm, and clear cells in central areas of follicle. Note also presence of mitotic figure amidst closely packed cells in centre of one follicle. Prominent nucleoli are visible in many of the cells (HE x 250).
Fig. 4. High-power magnification showing clear cellsin both peripheral and central areas of folliclesof ameloblastoma. Note also hyalinization of connective tissue (HE x 400).
Ameloblastoma o f mandible charged and has been followed clinically on a 3-monthly basis at the outpatient clinic. There has been no recurrence 5 years after the surgery.
malignant ameloblastoma, but, after review, this was interpreted as ameloblastic carcinoma. Discussion
Histopathology
The surgical specimen contained the resected part of the jaw from distal to left mandibular second molar and distal to the right second premolar. The lesion extended more lingually than labially or buccally (Fig. 1). Microscopic examination of multiple sections from the surgical specimen showed a dysplastic, parakeratotic, acanthotic, stratified, squamous epithelium overlying dense fibrous connective tissue infiltrated by follicles, nests, and anastomosing islands of neoplastic, odontogenic epithelial cells. These cells were continuous in areas with the overlying surface epithelium. The neoplastic follicles showed regular ameloblastomatous formations, while some showed clear cells in both the peripheral ameloblast-like cells and the central cells, where stellate reticulum-like cells are normally found. Cystic degeneration of the central cells was noted in some follicles. The ameloblastomatous tumour cells showed occasional mitoses, pl~0mifient nucleoli, and inductive effects on adjacent connective tissue; in areas, they showed penetration into the ne]ghbouring connective tissue (Figs. 2,-4). The stellate, reticulum-like cells were replaced in some areas by spindle cells, while hyperchromatic and pleomorphic tumour cells were seen in other areas. The lesion was initially diagnosed as
The case being reported is interesting for two reasons. Firstly, this is only the fourth reported case of intraosseous ameloblastoma with histologic evidence of clear-cell differentiation, two cases having been reported by WALDRON et al. 3 and one by MULLER & SLOOTV~EG1. Secondly, in spite of a diagnosis of ameloblastic carcinoma following an excisional biopsy, there has been no evidence of recurrence or reported metastasis after a 5-year follow-up. The absence of disease, 5 years after initial surgery, is probably explained by the radical nature of the surgical management applied. This leads us to ask whether this case should have been regarded as that of malignancy in the first instance. The histologic presentation was that of an ameloblastoma with atypical features, qualifying for malignancy. The outstanding feature in the histology was the presence of clear cells. The need to combine such an atypical feature with other features of cellular atypicality before a label of malignancy can be put on this lesion was highlighted in the case of clear-cell peripheral ameloblastoma reported by N 6 & SIAR2. They did not consider their case to be malignant because of the absence of other features of cellular atypicality. The case reported coincides with that of MULLER ~4 SLOOTWEGl in that age and location are the same.
359
The presence of clear cells in an ameloblastoma should not be surprising, because ameloblastomas are supposed to derive from the dental lamina, which has been reported to contain clear cells as one of its components4. The clear cells in clear-cell ameloblastoma have been reported to be rich in glycogenS. A retrospective study of the incidence of clear cells in ameloblastomas and odontogenic carcinomas is presently underway.
Acknowledgment. The authors are grateful to Mrs E O. Oduyoye, of the Department of Oral Biology and Oral Pathology, University of Lagos, for typing the manuscript. References
1. MULLERH, SLOOTWEGP. Celar cell differentiation in an ameloblastoma. J Max.fac Surg 1986: 14: 158-60. 2. NG KH, SIARCH. Peripheral ameloblastoma with clear cell differentiation. Oral Surg 1990: 70: 201-13. 3. WALDRONCA, SMALLIA, SILVERMANH. Clear cell ameloblastoma an odontogenie carcinoma. J Oral Maxillofac Surg 1985: 43: 707-17. 4. WYSOCKIGP, BRANNONRB, GARDNER DG, SAPVP. Histogenesis of the lateral periodontal cyst and the gingival cyst of the adult. Oral Surg 1980: 30: 327-34.
Address: Dr O. Odukoya Department of Oral Biology and Oral Pathology College of Medicine University of Lagos Lagos, Nigeria
