Introduction: Leontiasis ossea is the most severe bone complication of the maxillae of chronic renal failure. The objective of this work is to determine the clinical, paraclinical and therapeutic aspects of this condition. Observation: A 42-year-old patient with chronic anuric terminal renal failure dialysis for 12 years had consulted for multiple maxillo-mandibular swelling evolving for 2 years deforming the face with discomfort to chewing. The biological assessment was: PTH: 5252 pg/mL, Ca 2+ : 2.86 mmol/L, free T3: 4.16 pmol/L, free T4: 6.55 pmol/L, TSH: 3.13 U/mL, serum protein: 61 g/L, Creatinine: 835 µmol/L. The maxillofacial CT noted heterogeneous diffuse thickening of the cranial vault and bones of the facial massif evoking leontiasis ossea with right mandibular brown tumor. The biopsy diagnosed fibrous gingival epulis. The patient had undergone modeling surgery, under general anesthesia after dialysis, of the right mandibular tumor whose histological result was Leontiasis ossea. Conclusion: Treatment is modeling surgery under hemostatic control.