Recurrence of ameloblastoma in temporal area: primary treatment influences recurrence rate

Reconstruction of Deep Circumflex Iliac Artery Free Flap for Multiple Recurrent Ameloblastoma in Mandible

Ameloblastoma is the most common odontogenic tumor of epithelial origin. These tumors are benign in nature but have a high rate of recurrence and possible malignant development when treated inadequately. However, recurrent ameloblastomas in bone grafts are rare. This article presents a rare case of a multiple recurrent ameloblastoma, with the last recurrence in a nonvascularized free iliac bone graft of the mandible, reconstructed with vascularized deep circumflex iliac artery free flap for the surgical defect. Furthermore, an updated review of the literature on recurrent ameloblastomas affecting the bone graft is provided.

Recurrent Ameloblastoma: A Surgical Challenge

Ameloblastoma is locally aggressive benign odontogenic tumour with increased risk of recurrence rate. The choice of treatment depends on the histologic subtype. Radical therapy is the recommended modality for solid ameloblastomas. The possibilities of recurrence even after enbloc resection are still high. The author presents two case reports of recurrent ameloblastomas postradical resection. First case describes the recurrence of ameloblastoma in the bone graft which was used for reconstruction, and the second case depicts recurrence in the infratemporal fossa. Intraoperative radiography of the frozen section of the soft tissue margin plays an important role in the holistic management of these lesions.

Primary Ameloblastoma of the Temporal Bone

Ameloblastoma is a locally aggressive tumor derived from odontogenic epithelium. Although benign, its clinical behavior can often exhibit malignant characteristics. It is marked by slow and persistent growth with infiltration of adjacent tissues. Almost 70% occur in the mandible in patients older than 30 years. Recurrence of ameloblastoma from inadequate treatment is frequent. Because of its slow growth, recurrences can present decades after primary surgery. A primary ameloblastoma in an area outside the mandibular, maxillary, and infratemporal fossa regions has not been described in detail to date, with only 1 possible case mentioned in the literature. The authors present a case of primary temporal bone ameloblastoma in a 17-year-old boy. The tumor originated in the left mastoid, infiltrated the lateral semicircular canal, facial nerve, and cochlea, and adhered to the sigmoid sinus and posterior cranial fossa dura. Although invasion of multiple structures in the infratemporal fossa and temporal bone leads to variable disease presentation, this case is unique because the first symptom of disease was sudden and recurring unilateral sensorineural hearing loss. Surgery required transection of the facial nerve. Histopathology confirmed primary temporal bone ameloblastoma. The difficulties in achieving wide surgical margins, diagnostics, and further management are addressed.

Soft tissue recurrent ameloblastomas also show some malignant features: A clinicopathological study of a 15-year database

Background

To investigate the clinicopathological features of six cases of soft tissue recurrent ameloblastoma and explore the role of increased aggressive biological behavior in the recurrences and treatment of this type of ameloblastomas.

Material and Methods

In this study, we retrospectively reviewed recurrent ameloblastomas during a 15-year period; six cases were diagnosed as soft tissue recurrent ameloblastoma. The clinical, radiographic, cytological and immunohistochemical records of these six cases were investigated and analyzed.

Results

All the six soft tissue recurrent ameloblastomas occurred after radical bone resection, and were located in the adjacent soft tissues around the osteotomy regions. In Case 4, the patient developed pulmonary metastasis, extensive skull-base infiltration and cytological malignancy after multiple recurrences and malignant transformation was diagnosed. In the other five cases, although there were no cytological signs are sufficient to justify an ameloblastoma as malignant, some malignant features were observed. In Case 1, the tumor showed moderate atypical hyperplasia and the Ki-67 staining percentage was 40% positive, which are strongly suggestive of potential malignance. In Case 5, the patient developed a second soft tissue recurrence in the parapharyngeal region and later died of tumor-related complications. All the remaining three patients showed cytology atypia of varying degrees and high expression of PCNA or Ki-67, which confirmed active cell proliferation.

Conclusions

Increased aggressiveness is an important factor of soft tissue recurrence. An intraoperative rapid pathological examination and more radical treatment are suggested for these cases.

Key words: Ameloblastoma, soft tissue recurrence, aggressive biological behaviour.