Introduction: Lipomas are benign soft tissue tumors, characterized by the presence of mature adipocytes in histopathology. Their development is slow and their etiologies are still controversial. Frequently subcutaneous, this type of lesion is rarely present in the oral cavity. Observation: A 67-year-old man consulted for a nodule on the inner face of his right cheek which had been developing for several years, with severe discomfort during chewing. The typical clinical aspect of this lesion suggested a lipoma. Magnetic resonance imaging (MRI) was performed before surgical excision in order to establish a differential diagnosis with a well-differentiated liposarcoma. Comments: The various imaging examinations, particularly MRI, combined with the analysis of the fat component and the morphology of the non-fat component (septa) enable us to define several categories of lesions likely to have a benign or malignant character. However, some lesions remain difficult to classify, and it is the histopathological examination along with, if necessary, immunohistochemistry (anti-MDM2 and/or anti-CDK4), which allows to confirm or not the malignancy of a lesion. Histological examination suggested a fibrolipoma. Conclusion: Although benign, the size of a fibrolipoma may can lead to significant functional and aesthetic discomfort for the patient. Surgical excision remains the treatment of choice.