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.
Fig. 1: Axial T1 MRI image demonstrating a subcutaneous fatty lesion in the right groin.
Fig. 2: Axial STIR MRI image demonstrating complete suppression of the fatty lesion in the right inguinal subcutaneous lesion consistent with a benign lipoma, grade 1 lesion on our MRI grading system. MDM2 negative.
Grade 2: Subtle homogenous increase signal compared to the surrounding fat.
Fig. 3: Axial T1 MRI image demonstrating a subcutaneous fatty lesion in the back right of the midline.
Fig. 4: Axial STIR MRI image demonstrating subtle increased signal within the subcutaneous lesion on the back compared to the surrounding fat, grade 2 on our grading system. MDM2 negative.
Grade 3: Presence of non-fatty tissue with nodules and septations.
Fig. 5: Axial T1 MRI image demonstrating a subcutaneous fatty lesion in the right chest wall with some septations.
Fig. 6: Axial STIR MRI image demonstrating high signal intensity with some nodules and septations, grade 3 lesion on our system. This case was negative for MDM2.
Grade 4 :Liposarcoma
Fig. 7: Axial T1 MRI image demonstrating a large heterogenous intramuscular lesion in the anterior compartment of the left thigh.
Fig. 8: Axial STIR MRI image demonstrating diffuse high signal intensity within the large intramuscular lesion in the anterior compartment of the left thigh, grade 4 on our system consistent with a liposarcoma.
This grading can help the decision-making to biopsy the lesion.