Malignant transformation of a maxillary follicular ameloblastoma to squamous cell carcinoma: A case report and review of literature.

INTRODUCTION

Ameloblastoma is a benign but locally infiltrative epithelial odontogenic neoplasm of the jawbones. Ameloblastoma and squamous cell carcinoma commonly affect the mandible and maxilla. However, malignant transformation of ameloblastoma into squamous cell carcinoma is extremely rare.

CASE PRESENTATION: A 72-year-old man presented with a rapidly enlarging mass in the maxilla. Diagnostic imaging revealed a large mass with lytic changes involving the anterior and left aspects of the maxilla, and extending superiorly into the maxillary sinus. The patient underwent curettage treatment for a follicular ameloblastoma. The histological examination of the surgical resection specimen showed a close correlation between squamous cell carcinoma and ameloblastoma. On immunohistochemical analysis, staining for p53 and ki67 was positive in the squamous cells but not in ameloblastoma cells. The patient received subsequently radiation therapy with no evidence of recurrence 12 months post operatively.

DISCUSSION: Malignant transformation of ameloblastoma into squamous cell carcinoma is very rare, accounting for approximately 0.1 % to 1.8 % of all oral cancers. The first diagnostic challenge is to rule out the primary intraosseous squamous cell carcinoma using Gardner's criteria. In this case, the lesion was difficult to diagnose as a malignant transformation based only on intraoral examination and CT images. Histological and immunohistochemical analysis are gold standards for establishing the diagnosis.

CONCLUSION

In summary, this report aims to discuss the possibility of malignant progression of follicular ameloblastoma into squamous cell carcinoma through a literature review. We are also targeting to highlight the essential rule of histological and immunohistochemical studies to establish the diagnosis.