Septum-like structures in lipoma and liposarcoma: MR imaging and pathologic correlation

Area of Science:

• Radiology
• Oncology
• Pathology

Background:

• Lipomatous tumors encompass benign lipomas and malignant liposarcomas.
• Distinguishing between these entities is crucial for appropriate clinical management.
• Septum-like structures within lipomatous tumors can provide diagnostic clues.

Purpose of the Study:

• To investigate the characteristics of septum-like structures in lipomatous tumors.
• To correlate magnetic resonance imaging (MRI) findings with histopathologic features.
• To assess the utility of fat-suppressed MRI in differentiating liposarcoma from lipoma.

Main Methods:

• Analysis of MRI findings in 13 lipomatous tumors (3 well-differentiated liposarcomas, 1 dedifferentiated liposarcoma component, 9 lipomas).
• Acquisition of T1-, T2-, and fat-suppressed T1-weighted post-Gd-DTPA contrast-enhanced MRI sequences.
• Comparison of in-vivo MRI findings with ex-vivo MRI and histopathologic examination of surgical specimens from 5 patients.

Main Results:

• Fat-suppressed T1-weighted MRI effectively visualized enhancement patterns of septum-like structures.
• Liposarcoma exhibited thick, considerably enhancing septa.
• Lipoma showed thin, minimally enhancing septa, representing fibrous capsules.

Conclusions:

• Enhanced septum-like structures on fat-suppressed MRI can help differentiate liposarcoma from lipoma.
• The presence of muscle fibers within liposarcoma septa necessitates consideration of extensive surgical resection.
• Accurate differentiation impacts surgical planning and patient outcomes.