Condylar intramedullary intraosseous lipoma: Contribution of a new case and review of the literature

BACKGROUND Lipoma is the most common benign tumour of the human body, being intraosseous involvement very rare. Just 1 to 4% of all cases of lipoma are located in the oral cavity, only 0.1% being intraosseous. The jaw is its most uncommon bone location. Etiology of intraosseous lipoma (IOL) is unknown, although several theories have been proposed. Usually asymptomatic, the symptoms, when present, will depend on its location and size. Its origin may be intraosseous or juxtacortical. A biopsy is essential for diagnosis, and definitive treatment involves resection or curettage of the lesion. The aim of this paper is to present a new case of intramedullary intraosseous lipoma of the mandible with involvement of the left mandibular ramus and condylar neck. MATERIAL AND METHODS A case of intramedullary intraosseous lipoma (IOL) on the left mandibular ramus and condyle is presented. No history of trauma in temporomandibular joint existed. The radiology showed a radiolucent multi-lobulated lesion with values of attenuation in the range of fat. Curettage is performed and the histopathology showed a conglomerate of adipocytes without trabeculae, calcifications or atypia. RESULTS According to the bibliography 24 cases of mandibular IOL have been described. This is the second reported case of condylar involvement and the first with cortical expansion. CONCLUSIONS Lipoma intraosseous is a very rare benign bone neoplasm. Histology is required for the differential diagnosis from other radiolucent lesions. The IOL treatment is the curettage with a good prognosis, although malignant transformation to liposarcoma has been reported in other locations. It is a disease with a difficult differential diagnosis, therefore the publication of new cases is important. Key words:Intraosseous lipoma, lipoma, jaw tumour, condylar tumour.