A Well-Differentiated "Lipoma-Like" Liposarcoma Arising in a Recurrent Intramuscular Lipoma-A Case Report and Review of Literature

Abstract

Intramuscular lipoma and well-differentiated liposarcoma are hardly differentiated both clinically and histologically. Intramuscular lipoma is benign but easy to recur. Well-differentiated liposarcoma is regarded as low grade malignancy. It does not metastasize but may recur after surgery and in some rare cases de-differentiate to a high-grade sarcoma. Malignant transformation of well-differentiated liposarcoma in a preexisting lipoma is rare and only a few cases have been reported previously. Wide resection is the treatment of choice for both tumors to minimize the potential risk of recurrence. Histologically, three variants of well-differentiated liposarcoma can be distinguished and the ”lipoma-like” variant is the most common. We presented a 42-year-old male patient of left thigh well-differentiated liposarcoma which was diagnosed as recurrent intramuscular lipoma for four times over the past 10 years. Wide excision was performed and pathology revealed well-differentiated ”lipoma-like” liposarcoma. The pathological characteristics and management are described and the previous literatures are reviewed.