Purpose: To construct a scoring system to differentiate malignant liposarcomas from benign lipomas by comparing their clinical and magnetic resonance imaging (MRI) features.
Methods: Clinical and MRI features of 33 women and 33 men aged 17 to 83 (mean, 53) years who underwent resection of malignant liposarcomas (n=32) or benign lipomas (n=34) were reviewed.
Results: The 5 strongest predictors of liposarcoma were male gender, larger tumour maximum dimension, deep to fascia, thick non-fatty septum or nodule, and internal cystic change. A weighted scoring system was constructed using the 5 strongest predictors as: Z score=10X1+X2+12X3+15X4+10X5, respectively. A cut-off score of 35 was used; all 32 malignant liposarcomas and 4 of 34 benign lipomas scored >35. The cut-off score of ≤35 could predict 30 of 66 lipomatous tumours as benign with a negative predictive value of 100% (p<0.0001).
Conclusion: The 5 strongest clinical and MRI features were identified to construct a scoring system to differentiate malignant from benign lipomatous tumours. Further validation in independent populations is required.
Keywords: lipoma; liposarcoma.