The management of mandibular ameloblastoma is currently radical by many teams, to reduce the risk of recurrence. And this consists of interrupted mandibulectomy often in the course of a diagnosis based on radiological, clinical and epidemiological elements without prior histopathological certainty. The document provides a descriptive and cross sectional study with prospective data collection, conducted in the department of Maxillofacial and Aesthetic Surgery of the Mohammed 6 Teaching Hospital of Marrakech, describe the case a patient of ages 29 years, received for mandibular swelling evolving for 3 years with slowly increasing volume. The clinical and radiological signs simulating ameloblastoma. In place of an interrupted subtotal mandibulectomy that was usually planned, a simple biopsy was performed and the results favored an epidermoid cyst rather than an ameloblastoma. The indication of an enucleation with curettage supported was carried out in place of an interrupted mandibulectomy usually performed before this radio-clinical chart. The biopsy prior to any radical surgery for suspicion of ameloblastoma has two notorious advantages: the diagnostic confirmation and the typology of the ameloblastoma therefore the precision of its high invasiveness or not.