Giant dedifferentiated liposarcoma of the mandible

Dedifferentiated liposarcoma (DDLPS) is a rare and aggressive malignant soft-tissue tumour with a poor prognosis. This report describes a case of giant DDLPS in the oral cavity, arising in the mandible. A 65-year-old woman was referred to the authors' hospital with a mandibular swelling. A presumptive diagnosis of mandibular malignant tumour (DDLPS; T3N0M0, stage III) was made based on correlation of the clinicopathological features. Before radical surgery, a tracheostomy was performed, as there was narrowing of the pharyngeal cavity due to tumour growth. A bilateral supraomohyoid neck dissection, segmental mandibulectomy, and reconstruction with titanium plates and a free rectus abdominis musculocutaneous flap were performed under general anaesthesia. Neither neoadjuvant nor adjuvant chemoradiotherapy was administered. Immunohistochemistry was positive for MDM2, CDK4, and p16, and genetic testing showed amplification of the MDM2 and CDK4 genes. No evidence of recurrence was observed after 18 months of follow-up.