What is the most common type of retroperitoneal sarcoma?

Liposarcoma is the Most Common Retroperitoneal Sarcoma

The most common type of retroperitoneal sarcoma is liposarcoma (answer choice A). 1

Evidence Supporting Liposarcoma as the Most Common Type

According to the most recent UK guidelines for the management of soft tissue sarcomas (2025), retroperitoneal liposarcomas have specific characteristics that distinguish them from other retroperitoneal sarcomas:

• Retroperitoneal liposarcomas have poorly defined margins and an inherent higher risk for local recurrence 1
• They tend to recur locoregionally, while high-grade retroperitoneal sarcomas recur more often systemically 1
• Low-grade liposarcomas may recur late even after 10 years 1

Comparison with Other Retroperitoneal Sarcoma Types

The guidelines specifically discuss the characteristics of other retroperitoneal sarcomas, allowing for direct comparison:

1. Liposarcoma: Most common, with poorly defined margins and high risk for local recurrence 1
2. Leiomyosarcoma: Second most common, with more clearly defined borders, lower risk for local recurrence but higher risk for systemic metastasis 1
3. Solitary fibrous tumors: Less common, with low risk for local recurrence 1
4. Undifferentiated pleomorphic sarcomas (UPS): Usually separated from the retroperitoneum by the psoas fascia 1
5. Malignant peripheral nerve sheath tumors: Require sacrifice of the nerve of origin during resection 1

Recent case reports and research studies further confirm this finding:

• "Liposarcoma (LPS) represents the most common type of retroperitoneal sarcoma (RPS)" 2
• "The most common retroperitoneal sarcoma type is liposarcoma, which account for 20% of all sarcoma types and 40% of all retroperitoneal sarcomas (RPSs)" 3
• "The most common histologic types of RPS are liposarcoma and leiomyosarcoma" 4

Clinical Implications

Understanding that liposarcoma is the most common retroperitoneal sarcoma has important clinical implications:

• Surgical approach: Extended surgical approach may improve long-term local control for liposarcomas 1
• Resection often necessitates ipsilateral nephrectomy, hemicolectomy, psoas fascia/muscle resection and distal pancreatectomy/splenectomy 1
• Follow-up should be long-term, as low-grade liposarcomas may recur even after 10 years 1

Key Characteristics of Retroperitoneal Liposarcomas

• They can grow to enormous sizes before detection due to the large potential space in the retroperitoneum 2, 3
• They often present late with nonspecific symptoms 2
• They have a high rate of local recurrence, which is the main cause of death 5
• Complete surgical resection offers the best chance for cure 5

In conclusion, based on the most recent and highest quality evidence, liposarcoma is definitively the most common type of retroperitoneal sarcoma.