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

## TL;DR

A rare case of a benign jaw tumor turning into squamous cell carcinoma is reported, emphasizing the need for detailed histological and immunohistochemical analysis for accurate diagnosis.

## Contribution

This case report highlights the rare malignant transformation of follicular ameloblastoma into squamous cell carcinoma and underscores the importance of histological and immunohistochemical studies for diagnosis.

## Key findings

- Malignant transformation of ameloblastoma into squamous cell carcinoma is extremely rare, occurring in 0.1% to 1.8% of oral cancers.
- Histological and immunohistochemical analysis is essential for diagnosing malignant transformation, as clinical and radiological findings alone are insufficient.
- Early surgical resection combined with adjuvant radiotherapy is effective in preventing recurrence.

## Abstract

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.

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.

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.

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.

•Malignant transformation of ameloblastoma into squamous cell carcinoma is extremely rare.•Malignant transformation of an ameloblastoma may be suspected based on clinical and radiological findings, however, the diagnosis is made through histological and immunohistochemical examination of a representative biopsy sample.•Early surgical resection followed by adjuvant radiotherapy remains the treatment of choice for avoiding recurrence.•Close monitoring and careful follow-up are essential for the early detection of any signs of recurrence. Its frequency depends on each individual case.

Malignant transformation of ameloblastoma into squamous cell carcinoma is extremely rare.

Malignant transformation of an ameloblastoma may be suspected based on clinical and radiological findings, however, the diagnosis is made through histological and immunohistochemical examination of a representative biopsy sample.

Early surgical resection followed by adjuvant radiotherapy remains the treatment of choice for avoiding recurrence.

Close monitoring and careful follow-up are essential for the early detection of any signs of recurrence. Its frequency depends on each individual case.