Ameloblastoma is a benign, odontogenic tumor that, due to its low rate of incidence, slow growth and local invasiveness, can be treated with a variety of surgical approaches, ranging from conservative to radical procedures. The conventional variant of ameloblastoma, though, is more aggressive and common, presenting a higher rate of recurrence than the unicystic and extraosseous/peripheral types; usually, the treatment of choice for this variant employs more invasive procedures. This report is of a 13-year-old male patient who presented with a swelling on the posterior mandibular region, on the left side of his face. Intraoral examination revealed lingual displacement of teeth 36 and 37. The clinical, radiographic and histopathological analyses confirmed the diagnosis of ameloblastoma (plexiform histological type). The patient was treated with curettage and peripheral osteotomy and a 5-year follow-up examination showed the area to have healed completely, with no evidence of recurrence. Consequently, although the clinical management of ameloblastoma is often based on invasive surgical approaches, large tumors treated with conservative surgery are less aesthetically and functionally impaired, and may demonstrate good prognosis with no recurrence in the 5-year follow-up period, as in the case reported here.