Retroperitoneal liposarcomas: Follow‐up analysis of dedifferentiation after clinicopathologic reexamination of 86 liposarcomas and malignant fibrous histiocytomas

• Published in: Cancer Vol. 106; no. 12; pp. 2725 - 2733
• Main Authors: Fabre‐Guillevin, Elizabeth, Coindre, Jean‐Michel, Somerhausen, Nicolas de Saint Aubain, Bonichon, Francoise, Stoeckle, Eberhard, Bui, Nguyen Binh
• Format: Journal Article
• Language: English
• Published: Hoboken Wiley Subscription Services, Inc., A Wiley Company 15-06-2006; Wiley-Liss
• Subjects: Adult; Aged; Biological and medical sciences; Cell Differentiation; dedifferentiated liposarcoma; dedifferentiation; Disease Progression; Female; Follow-Up Studies; Histiocytoma, Malignant Fibrous - diagnosis; Histiocytoma, Malignant Fibrous - mortality; Histiocytoma, Malignant Fibrous - pathology; Histiocytoma, Malignant Fibrous - surgery; Humans; Liposarcoma - diagnosis; Liposarcoma - pathology; Liposarcoma - surgery; Male; malignant fibrous histiocytoma; Medical sciences; Middle Aged; Neoplasm Recurrence, Local; Prognosis; Retroperitoneal Neoplasms - diagnosis; Retroperitoneal Neoplasms - pathology; Retroperitoneal Neoplasms - surgery; retroperitoneum; Retrospective Studies; sarcoma; Survival Rate; Tumors; well‐differentiated liposarcoma; Pseudotumor; malignant fibrous histiocytoma; Retroperitoneal; Sarcoma; retroperitoneum; well-differentiated liposarcoma; Malignant tumor; dedifferentiated liposarcoma; Cancerology; Fibrous histiocytoma; Histopathology; Dedifferentiation; Malignant histiocytoma; Liposarcoma; Xanthogranuloma; Adipose tissue disorders; Benign neoplasm
• ISSN: 0008-543X; 1097-0142
• DOI: 10.1002/cncr.21933

BACKGROUND
Dedifferentiated liposarcoma (DDL) juxtapose components of well‐differentiated liposarcoma (WDL) and nonlipogenic sarcoma. Malignant fibrous histiocytoma (MFH) is no longer considered a homogeneous entity, but rather as the common morphologic appearance of various subtypes of sarcomas. The objectives of the current retrospective study were: 1( to analyze the relation between DDLs and tumors previously diagnosed as MFHs; 2) to trace the evolution of liposarcomas, and 3) to assess the consequences of dedifferentiation.
METHODS
Between 1974 and 2001, 86 patients with retroperitoneal liposarcoma (61 patients) or MFH (25 patients) underwent surgery at Institut Bergonie in Bordeaux, France. Histologic review was performed and tumors reclassified as WDL or DDL were retained for further clinicohistologic study. Subsequently, initial presentation and all recurrences were analyzed.
RESULTS
The 61 liposarcomas consisted of 21 WDLs and 35 DDLs; 17 MFHs were reclassified as DDL. In all, approximately half of the retroperitoneal liposarcomas and MFHs were found to be DDLs. The DDLs presented with a smaller size (20 cm vs.30 cm; P = .05) but a lower rate of complete resection (72% vs.90%; P = .015) and remission (72% vs. 100%; P = .0015). Dedifferentiated recurrence was evidenced in 7 WDLs. Ten DDLs presented with metastatic evolution. DDLs demonstrated a tendency toward lower rates of 5‐year overall survival (55% vs. 82%; P = .075).
CONCLUSIONS
Most occurrences of retroperitoneal liposarcomas and MFHs are in fact DDLs and dedifferentiated recurrence of WDLs is frequent. Retroperitoneal DDLs present a lower rate of complete remission than WDLs and a risk of metastatic recurrence. Therefore, extensive histologic analysis of WDLs is required to identify an undifferentiated component and avoid misdiagnosis of DDL. Cancer 2006. © 2006 American Cancer Society.
The incidence of dedifferentiated liposarcomas (DDLs) is largely underestimated and most retroperitoneal liposarcomas and malignant fibrous histiocytomas are in fact DDLs. The crucial importance of avoiding misdiagnosis of DDLs was stressed because these tumors present poorer outcome than well‐differentiated liposarcomas.