To assess the positivity of Murine Double Minute 2 (MDM2) expression in atypical lipomas according to their anatomical location and MRI features to guide the need for biopsy.

21 patients referred to the Peninsula Sarcoma MDT in the southwest of England, with atypical lipomas over a period of one year were reviewed. Histology, MDM2 results and features on MRI were reviwed. We propose a grading system based on the MRI features: Grade 1: Benign; homogenous suppression on STIR. MDM2 negative. Grade 2: Subtle homogenous increase signal compared to the surrounding fat. Grade 3: Presence of non-fatty tissue with nodules and septations. Grade 4 :Liposarcoma This grading can help the decision-making to biopsy the...

Total number of patients with atypical lipomas referred to the Peninsula Sarcoma MDT betweenAugust 2017 and September 2018 andhad MDM2 tested were 23; sixteen from Plymouth, and seven from Cornwall. Seven lesions were MDM2 positive. However, two cases were excluded: 1 MDM2 not performed 1 recurrent mesenteric liposarcoma (MDM2 +ve) The total number after exclusions= 21. The 21 lesions were divided into retroperitoneal and non-retroperitoneal. — The non-retroperitoneal were further categorised based on the anatomy into extremity lipomas (10) and torso lipomas (6). They were...

MDM2 is a novel yet an important immunohistological marker in assessing the malignant potential of atypical lipomas. This marker in conjunction with MR features can help streamline the diagnostic approach of atypical lipomas. Further studies with a bigger study sample has been planned to confirm our initial results from this small sample study.

S. Al-Qassab, Radiology Registrar, Plymouth University Hospital, UK P. Suresh, Consultant MSK Radiologist, Plymouth University Hospital, UK L. Farmkiss, Pathology Registrar, Plymouth University Hospital, UK K. Syred, Consultant Histopathologist, Plymouth University Hospital, UK