Recurrent Ameloblastoma of the Mandibular Ramus Resected Using a Modified High Perimandibular Approach: A Case Report.

Ameloblastoma typically lacks a well-defined capsule and exhibits locally invasive growth, making them prone to recurrence. On the other hand, a subtype known as the unicystic type is generally well circumscribed and less invasive compared with conventional solid/multicystic variants, but recurrence may occur in rare cases. Therefore, after tumor removal, it is essential to resect or curette the adjacent bone surface that may have been infiltrated. The high perimandibular approach is a surgical technique originally developed for treating condylar fractures. It involves a 4-5 cm skin incision placed 5 mm below the lower border of the mandible, followed by incision of the platysma and masseter muscles above the course of the mandibular branch of the facial nerve, thereby protecting the nerve. Compared with other surgical approaches, this method provides a wide operative field and superior esthetic outcomes, as postoperative scars are less conspicuous. In this report, we describe a case in which this approach was adapted for resecting a recurrent ameloblastoma of the mandibular ramus. The patient was a 58-year-old man who presented to our department in May 2016 with a lesion extending from the right mandibular body to the mandibular ramus. A diagnosis of ameloblastoma unicystic type was established, and fenestration procedures were performed in May 2017. However, further treatment was discontinued at the patient's request. The tumor subsequently recurred on the lateral surface of the right mandibular ramus, measuring 28 mm × 14 mm. In May 2022, the lesion was resected using the extended high perimandibular approach: an extended incision of 10 cm, twice the usual length, provided sufficient surgical exposure to allow for safe and effective complete tumor removal. Postoperatively, no facial nerve paralysis occurred, and no recurrence was observed during 3 years of follow-up. Esthetic outcomes were satisfactory. In conclusion, the extended high perimandibular approach may be a useful surgical option for managing recurrent ameloblastoma on the lateral surface of the mandibular ramus.