Age / Sex : 58 / M

C.C.: A mass noticed at the right calf incidentally 

PHx: nephrectomy due to renal cell carcinoma

Liposarcoma

Discussion

Findings:
- Axial T1-weighted, T2-weighted and enhanced T1-weighted images show a mass between the gastrocnemius and soleus muscles. It has well-enhancing nodular component and fat-components with numerous septa.

Diagnosis: Liposarcoma

Discussion:
- Liposarcoma is histologically classified into five subtypes according to the most recent (2002) World Health Organization (WHO) classification: (a) well-differentiated; (b) dedifferentiated; (c) myxoid; (d) round cell; and (e) pleomorphic.
- Dedifferentiated liposarcoma represents a biphasic neoplasm, with one component being a well-differentiated liposarcoma and the other a non-adipose cellular sarcoma, mainly fibrosarcoma. Overall, dedifferentiation occurs in approximately 10% of well-differentiated liposarcomas. A non-lipomatous tissue, nodular dominant focus (>1 cm in size) in a well-differentiated liposarcoma seen in CT or MRI suggests dedifferentiated liposarcoma. The clinical behavior of dedifferentiated liposarcoma, which reflects the high-grade histological characteristics, is more aggressive than well-differentiated liposarcomas. Thus, the treatment approach and prognosis are different. Dedifferentiated liposarcomas are treated with wide surgical excision and frequently with radiation therapy; chemotherapy may also be used as an adjunct.

References:
1. Liyuan Yu, Sungmi Jung, Leonard Hojnowski, and Timothy Damron. Best Cases from the AFIP: Dedifferentiated Liposarcoma of Soft Tissue with High-Grade Osteosarcomatous Dedifferentiation. RadioGraphics 2005; 25:1082-1086
2. Mark D. Murphey, Lynn K. Arcara, and Julie Fanburg-Smith. From the Archives of the AFIP: Imaging of Musculoskeletal Liposarcoma with Radiologic-Pathologic Correlation. RadioGraphics 2005 25: 1371-1395