[Multiple metastases of a mandibular ameloblastoma].

INTRODUCTION

Ameloblastoma is a benign odontogenic tumor which can be locally aggressive and invasive. Metastases are rare but possible and must be considered as a malignant form of the tumor.

OBSERVATION: A 50-year-old woman presented a jugal metastasis of a mandibular ameloblastom which had been treated several times 28 years earlier. Six months after resection of the metastasis, the patient developed multiple cervical node metastases which were removed by radical curettage. Five months later, new metastases developed on the scalp and three months later a voluminous metastasis involving the right hemiface extended to the base of the skull. Surgical resection was only partial followed by radiotherapy. Ten months later the outcome was favorable.

DISCUSSION: The absence of any histological sign of malignity in the primary tumor and in the metastases, as observed in our patient, is remarkable. Metastases generally develop in the lung (61-80% of cases). Metastases to the scalp have never been described. The time to development of a metastasis is generally very long and metastases usually remain asymptomatic. Progression is very slow, like for the primary tumor. Several factors predictive of metastasis have been described: female gender, age at onset of primary tumor (2nd to 3rd decade) and multiple local recurrences. There is no standard treatment for metastases. Chemotherapy is not effective. Radiotherapy may be effective, particularly when lesions are not accessible to surgery. Surgical resection remains the treatment of choice.