Metastasizing ameloblastoma of the breast: A case report

Ameloblastomas are slow growing and locally aggressive odontogenic tumors with a high propensity for recurrence. It frequently arises in the mandible and has been reported to metastasize commonly in the lungs. An updated World Health Organization classification re-categorized metastasizing ameloblastomas under benign tumors. Other rare metastatic sites include the skull, maxilla, kidney, and liver.

We present a 53-year-old female with a gradually enlarging right breast mass for 2 years. She previously underwent right hemimandibulectomy with clavicular bone grafting 15 years ago for a primary ameloblastoma. Preoperative imaging showed a resectable, heterogenous right breast mass with a biopsy revealing spindle cell neoplasm. She subsequently underwent radical mastectomy with a latissimus dorsi myocutaneous flap as a reconstructive procedure. Histopathologic findings were consistent with a metastasizing ameloblastoma. The patient remains disease-free as of most recent follow-up.

There are several proposed mechanisms for metastasizing ameloblastomas. Based on the history and location of the tumor, we surmised that tumor seeding from the first surgery done 15 years ago may explain this rare occurrence. Preoperative imaging and biopsy determine resectability and surgical approach. Radical surgery is frequently performed which largely depends on the site of the tumor. Complete primary resection with adequate margins remains to be the treatment of choice to prevent recurrence or metastasis. The role of adjuvant radiotherapy or chemotherapy are still to be established.

This case highlights the value of history-taking and having a high-index of suspicion for metastasis several years after primary resection of ameloblastomas.