De-differentiated giant thigh liposarcoma disguised as recurrent lipoma; a case report

INTRODUCTION AND IMPORTANCE: Lipomas are one of the commonest soft tissue tumors which usually arise from subcutaneous plane. Lipomas can progress to one of the three types of liposarcomas. Dedifferentiated liposarcomas have metastasis potential, risk of recurrence and increased risk of mortality. The culture of taking every lipoma as benign should be seriously considered with different approaches as it can lead to sarcomatous degeneration in some cases. CASE PRESENTATION: A 78 years old male patient present to our hospital with recurrent left thigh swelling of two years duration with limping and sense of heaviness on left side. He has history of previous surgery for the same complaint on the same site two times, six and four years ago. Histological diagnosis in both cases was lipoma. Objectively he has 20 × 60 cm non tender, soft to firm, slightly mobile swelling on left thigh spanning anterior, lateral and posterior compartment but no inguinal swelling. Fine needle aspiration cytology from the mass reported sarcoma. CT-scan stated diagnosis as sarcomatous tumor. CLINICAL DISCUSSION: Lipoma is commonest soft tissue tumor arising from adipocytes more often in young adults, women and overweight population. Well-differentiated liposarcoma can progress to dedifferentiated liposarcoma over time which is slightly aggressive than its precursor. Management of liposarcoma depends on stage, site and histology. Surgical resection with radiotherapy is the standard of care for localized dedifferentiated liposarcomas. CONCLUSION: It is difficult to differentiate between giant lipoma and well-differentiated liposarcoma with physical examination and imaging. Histopathologic examination in uncertain conditions will decrease morbidity and mortality from the more aggressive forms of liposarcomas.